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VIRGINIA GEOLOGICAL SURVEY 

UNIVERSITY OF VIRGINIA 

Thomas Leonard Watson, Ph. D. 

DIRECTOR 


Bulletin No. VII 


Geology of the Gold Belt in 
the James River Basin 
Virginia 


By STEPHEN TABER 
Assistant Geologist 







I 


VIRGINIA GEOLOGICAL SURVEY 

UNIVERSITY OF VIRGINIA 

Thomas Leonard Watson, Ph. D. 

* DIRECTOR 


Bulletin No. VII 

4 rr 


Geology of the Gold Belt in 
the James River Basin 
Virginia 


By Stephen Taber 

n 

ASSISTANT GEOLOGIST 


S 

CHARLOTTESVILLE 
University of Virginia 
* 9*3 


i 


jf 












B;v Transfer 

OCT 22 


















STATE GEOLOGICAL COMMISSION 


William Hodges Mann, Chairman, 
Governor of Virginia. 

E. A. Alderman, 

President of the University of Virginia. 

P. B. Barringer, 

President of the Virginia Polytechnic Institute. 
E. W. Nichols, 

Superintendent of the Virginia Military Institute. 
A. M. Bowman, 

Member of the House of Delegates. 


Thomas Leonard Watson, 
Director of the Survey. 




CONTENTS 


Page 

Illustrations . *} 

Letter of Transmittal . xii 

Introduction . 

Acknowledgments . 1 

Chapter T.—Geography and History. 

Location . 2 

Topography . 

Drainage . 3 

Soil . 4 

Climate . 4 

Culture . 4 

History . 5 

Production . 9 

Previous geologic work. > . 9 

Chapter II.—Descriptive Geology and Petrography. 13 

Introduction . 13 

Rocks sedimentary in origin. 14 

General classification . 14 

Pre-Cambrian .. . . 14 

General statement . 14 

Quartzites . 15 

General character and distribution. 15 

Details of occurrences. 16 

Bremo Bluff . 16 

Tellurium mine . 18 

London and Virginia mine. 19 

Ferruginous quartzites . 19 

General character and distribution. 19 

Details of occurrences. 19 

Webb tract . 19 

Ayre tract . 20 

Scotia mine . 21 

Other localities . 21 

Garnetiferous quartzites . 22 

General character and distribution.... 22 

Details of occurrences. 22 

Lantana . 22 

Stage Junction . 23 

Hornblende-bearing quartzites . 23 

Quartz-sericite schists . 23 

General character and distribution. 23 

Genesis . 24 

Details of occurrences. 24 

Big Byrd Creek. 24 

Lantana . 24 

New Canton-Dillwyn road. 25 

London and Virginia mine. 25 

Bondurant mine . 26 

Other localities . 26 

Cyanite schists . 26 

General character and distribution. 26 

Genesis . 27 

Details of occurrences. 27 

Willis Mountain . 27 

Trent farm . 28 

Knotted schists . 29 

General character and distribution. 29 

Details of occurrences. 30 





























































CONTENTS v 

Page 

New Canton . 30 

Strathmore . 34 

The Tellurium schists. 34 

Stage Junction . 34 

Hornblende schists . 34 

General character and distribution. 34 

Details of occurrences. 35 

New Canton . 35 

Big Byrd Creek. 35 

Lantana . 36 

Gneisses . 36 

General character and distribution. 36 

Genesis . 37 

Details of occurrences. 38 

Young American mine. 38 

Bowles’ bridge . 38 

Bertha and Edith mine. 38 

Belzoro mine . 39 

Ordovician . 39 

General statement . 39 

Conglomerate . 40 

General character and distribution. 40 

Details of occurrences. 41 

Penlan . 41 

Carysbrook . 41 

Long Island Creek. 42 

Quartzite . 42 

Schist . 42 

Tuff . 43 

Slate . 43 

General character and distribution. 43 

Details of occurrences. 44 

Arvonia . 44 

Bluffs along James River. 45 

Carysbrook . 45 

Triassic . 46 

Rocks igneous in origin. 47 

General classification . 47 

Pre-Cambrian . 47 

Greenstone schists . 47 

General character and distribution. 47 

Age . 49 

Details of occurrences. 49 

Slate River . 49 

Lightfoot farm . 50 

Anaconda mine . 50 

Shores . 51 

Hughes mine . 51 

Palmyra . 51 

Quartz-feldspar porphyries . 51 

Rhyolites . 52 

General description and age relations. 52 

Details of occurrences. 52 

Bremo Bluff . 52 

Slate River . 52 

Ballinger Creek . 52 

Palmyra . 53 

Pre-Cambrian and Cambrian. 53 




























































VI 


CONTENTS 


Page 

Granites, their associated pegmatites, and hornblende schists. 53 

Introductory statement . 53 

Age . 54 

Cartersville area .. ■ • 54 

General description . 54 

Detailed descriptions . 55 

Pemberton . 55 

Cartersville . 56 

Stokes . 56 

Elk Hill complex. 57 

General description . 57 

Detailed descriptions . 57 

Pegmatite belt . 59 

General description . 59 

Detailed descriptions . 59 

James River section. 59 

Little Byrd Creek. 60 

Lantana . 61 

Bula . 61 

Shannon Hill . 61 

Dickey farm . 61 

Other localities . 62 

Columbia area . 62 

General description . 62 

Detailed descriptions . 64 

Columbia . 64 

Big Byrd Creek. 68 

Lantana . 69 

Tabscott . 70 

Payne farm . 70 

Trent farm . 71 

Trenton Mills . 71 

New Canton . 71 

Stearnes . 72 

Fork Union . 75 

Rivanna Mills. 73 

Carysbrook bridge . 75 

Carysbrook . 75 

Gold Hill granite area. 77 

General description . 77 

Detailed descriptions ... 78 

McGloam mine . 78 

Big Byrd Creek. 79 

Hughes farm . 80 

Rosney granite area. 80 

Granite at Greeley mine. 82 

Porphyries . 82 

Distribution and general description. 82 

Details of occurrences. 82 

Cambrian or Post-Cambrian. 84 

Diorite dikes . 84 

Distribution and general character. 84 

Age . 84 

Details of occurrences. 84 

Palmyra . 84 

Long Island Creek. 85 

Benton mine . 85 

Bowles mine . 85 

Triassic . 85 





























































CONTENTS 


vii 
Page 

Diabase dikes . 85 

Distribution and general character. 85 

Details of occurrences. 86 

Columbia . 86 

Grannison mine . 86 

Pemberton . 87 

Dillwyn . 87 

Other localities . 87 

Chapter III.—Physiography . 88 

Introduction . 88 

Relief . 88 

Drainage . 91 

Physiographic history . 93 

Chapter IV.—Structure and Metamorphism. 98 

Introduction . 98 

Structural features . 98 

Folding . 98 

Faulting . 100 

Jointing . 100 

Schistosity . 101 

Structural relations of the granite. 102 

Relation of the hornblende schists to the granites. 103 

Metamorphic features . 105 

Regional metamorphism . 105 

Contact metamorphism . 106 

Introduction . 106 

Detailed descriptions of contact phenomena. 107 

James River section across granite contact. 107 

Rivanna River section across granite contact. 112 

Veins . 113 

Willis Mountain . 113 

Outline of geological history. 114 

Pre-Cambrian . 115 

Cambrian . 115 

Ordovician . 116 

Triassic . 116 

Chapter V.—The Gold Mines of the District. 118 

Introduction . 118 

Mines in Goochland and Fluvanna counties. 118 

The Young American mine. 118 

Location . 118 

History . 118 

Present equipment . 119 

Underground development . 119 

General description of geology. 120 

Detailed description of veins and wall rock. 122 

The Belzoro mine. 139 

Location . 139 

History . 139 

Descriptive geology . 140 

Production . 141 

The Collins mine. 141 

The Morgan mine. 141 

The Grannison mine. 142 

The Atmore, Kent, and other properties. 142 

The Bertha and Edith mine. 142 

Location . 142 

History . 142 




























































CONTEXTS 


viii 

Page 

Description of veins and country rock... 143 

The Pryor tract. 144 

The Moss mine. 144 

Location . 144 

History . .. 144 

Descriptive geology . 145 

The Busby mine. 146 

The Payne tract. 147 

The Waller mine. 148 

Location . 148 

History . 148 

Descriptive geology . 148 

The Fleming mine. 151 

Location . 151 

History and description. 151 

Shannon Hill . 151 

The Benton mine. 152 

Location . 152 

Description . 152 

The Tellurium mine. 152 

Location . 152 

History and description. 153 

Present underground development. 155 

The Tellurium vein system. 155 

Introduction . 155 

General description of veins and country rock. 155 

Detailed description of veins and wall rock. 157 

The Scotia mine. 172 

Location .. 172 

History and description. 172 

Gold prospects southwest of the Scotia mine. 173 

The Bowles mine. 175 

Location . 175 

History and general description. 175 

The Gold Hill vein system. 176 

Introduction . 176 

Country rock . 176 

The McGloam mine. 177 

The Shaw mine. 178 

The Bowles mine. 178 

The Page mine. 179 

The Snead mine. 180 

Location . 180 

History . 180 

Geology . 180 

The Hughes mine. 181 

Location . 181 

History . 181 

Equipment . 181 

Underground development and description of veins. 182 

Geology of veins and country rock. 182 

Mines in Buckingham County. 183 

The London and Virginia mine. 183 

Location . 183 

History . 183 

Descriptive geology . 184 

Description of vein . 187 


/ “ v ^ 



























































CONTENTS 


IX 


Page 

The Buckingham mine. 190 

Location . 190 

History . 190 

Geology of the ore body. 191 

The Williams mine. 191 

Location . 191 

Description . 191 

The Bondurant mine. 192 

Location . 192 

History . 192 

Descriptive geology . 193 

The Anderson mine. 195 

Location . 195 

Description . 195 

The Llood mine... 195 

Location .•. 195 

Description . 195 

The Gilliam mine. 195 

The Burnett mine. 196 

Location . 196 

Histoiy . 196 

Descriptive geology . 196 

The Hobson tract. 197 

The Morton mine. 197 

Location . 197 

Histoiy . 197 

Geology . 197 

The Morrow mine. 198 

Location . 198 

History . 198 

Production . 199 

Underground development . 200 

Descriptive geology . 200 

Description of ores. 204 

Placers . 205 

The Seay mine. 205 

The Greeley mine. 205 

Location . 205 

History .. 205 

Veins and country rock. 206 

The Liglitfoot mine. 207 

Location . 207 

History .. 207 

Gold veins . 207 

Chapter VI.—Genetic Relations of the Gold Deposits. 208 

Introduction . 208 

Previous theories . 208 

Types of deposits. 209 

Mineral composition of the veins. 209 

List of minerals present in the gold veins. 211 

Description of the gangue minerals. 213 

Description of the ore minerals. 214 

Summary . 215 

Genesis of the deposits. 216 

Nature of the solutions. 217 

Source of the materials. 219 

Deposition of the ores. 221 

Origin of the spaces occupied by the veins. 222 




























































X 


CONTENTS 


Page 

General conclusions as to the origin of the gold deposits. 231 

Secondary enrichment . 232 

Age of the ore deposits. 233 

Chapter VII.—Placers . 235 

Chapter VIII.—Description of Copper Mines and Prospects. 241 

Types of copper deposits. 241 

Description of individual mines. 241 

The Lightfoot mine. 241 

Location . 241 

History . 241 

Country rock . 241 

Ore deposit . 242 

The Bumpus property. 243 

The Ford property. 243 

The Anaconda mine. 243 

Location . 243 

History . 243 

Descriptive geology . 244 

Genesis of ores at the Lightfoot and Anaconda mines. 244 

The New Canton mines. 246 

History . 246 

The Johnson mine. 247 

The McKenna mine. 247 

The Hudgins mine. 248 

The Margaret mine. 248 

General description of the geology. 248 

Detailed description of the ore and inclosing rock. 250 

The Margaret mine. 250 

The McKenna mine. 253 

The Johnson mine. 254 

The Hudgins mine. 256 

Genesis of the New Canton ore deposits. 257 

Comparison with other ores of the district. 259 

Bibliography of the Gold Belt in the James Biver Basin. 260 

Index . 262 





































ILLUSTRATIONS 


Plate 

I. 

II. 

III. 


IV. 

V. 


VI. 


VII. 

VIII. 

IX. 

X. 


Figure 

1 . 

2 . 

3. 

4. 

5. 

6 . 

7. 

8 . 

9. 

10 . 

11 . 

12 . 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20 . 
21 . 
22 . 
23. 


Facing Page 


Topographic and geologic map of the gold belt in the Janies River 

Basin, Virginia .in pocket 

Detailed geologic map of the gold belt on the north side of James 

River in Goochland and Fluvanna counties, Virginia.... in pocket 
Fig. 1. Looking up James River from Bremo bridge. Rapids due to 

quartzite beds . 18 

Fig. 2. Quartzite cliffs near north end of bridge; looking northeast IS 

Fig. 3. Nearer view of quartzite cliffs, north side of James River at 

Bremo Bluff . 18 


Fig. 1. Cyanite schists outcropping near summit of Willis Mountain 28 
Fig. 2. Cyanite schists outcropping on the Trent farm. 28 

Fig. 1. Photomicrograph of biotite-bearing knotted schist, thin section 

cut perpendicular to schistositv. 30 

Fig. 2. Photomicrograph of garnetiferous knotted schist, thin section 

cut parallel to schistosity. 30 

Fig. 1. Ordovician sediments resting on eroded surface of massive 

granite, Carysbrook . 42 

Fig. 2. Looking north along summit of Willis Mountain. Piedmont 

peneplain in background. 42 

Fig. 1. Bed of tuff in Ordovician slates. Bluffs on south side of 

James River . 43 

Fig. 2. Fault in Ordovician slates. Bluffs on south side of James River 43 
Fig. 1. Flow structure in banded gneiss intruded between layers of 

hornblende schist . 57 

Fig. 2. Photomicrograph of plagioclase feldspar in vein quartz from 

the Waller mine. 57 


Map of surface and underground workings, Young American mine. ... 119 

Fig. 1. Cyanite in vein quartz from Young American mine. 128 

Fig. 2. Lenses of vein quartz in gneiss, Young American mine. 128 


Page 


Index map showing location of area. 2 

Geologic map of Arvonia-New Canton area. 17 

Pegmatite dike cutting granite near Rivanna Mills. 74 

North end of Willis Mountain from the west. 90 

South end of Willis Mountain from the west. 90 

Vertical section of “Sulphur” vein, Y r oung American mine. 123 

Sketch of vein at the Young American mine. 127 

Vertical section showing vein quartz in a sheared zone, Young Ameri¬ 
can mine . 130 

Quartz lenses in a shear zone, Young American mine. 130 

Vertical section through “H. V.” shaft and “Sulphur” vein, Young 

American mine . 132 

Sketch showing distribution of vein quartz, Young American mine... 137 

Quartzite bed cut by gold-bearing veins, Tellurium mine. 158 

Symmetrical lenses in “Middle” vein, Tellurium mine. 165 

Large lens composed of smaller lenses. “Middle” vein, Tellurium mine 166 

Small fault cutting the “Middle” vein. Tellurium mine. 167 

Lenticular bed of ferruginous quartzite, Scotia mine. 171 

Geologic map of Dillwyn and vicinity. 185 

Quartz veinlets cutting quartzite, Bondurant mine. 194 

Geologic section at the Morrow mine. 202 

Reticulated veinlets with inclusions of wall rock at the Morrow mine. . 204 

Sketch showing recrystallization of quartz about garnets in schist.... 227 
Sketch showing radial arrangement of quartz in garnetiferous schist.. 228 
Diagrammatic section of ore-body at the Margaret mine. 251 

































LETTER OF TRANSMITTAL 


Virginia Geological Survey, 

University of Virginia, 

Charlottesville, 1913. 

To His Excellency, Hon. Win. Hodges Mann, Governor of 

Virginia, and Chairman of the State Geological Commission. 

Sir:—I have the honor to transmit herewith for publication as Bulletin 
No. VII of the Virginia Geological Survey Series of Reports, a report 
entitled “Geology of the Gold Belt in the James River Basin, Virginia,” by 
Dr. Stephen Taber, Assistant Geologist on the Virginia Geological Survey. 

This report is the first of a series planned by the State Survey to cover 
the geology of the entire gold belt in Virginia, and it should prove of 
much value to those seeking information on the gold deposits of the area 
mapped and studied, including the counties of Buckingham, Cumberland, 
Fluvanna, and Goochland. 

Respectfully submitted, 

Thomas L. Watson, 

Director. 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER 

BASIN, VIRGINIA 

BY STEPHEN TABER. 

INTRODUCTION 

This report is a geologic and economic investigation of the Gold Belt 
in the James River Basin, Virginia, an area comprising 700 square miles 
in Fluvanna, Goochland, Buckingham, Cumberland, Powhatan, and 
Amelia counties. The occurrence and origin of the gold, copper, and sul¬ 
phide deposits within the area are discussed in detail. The commercial 
slates of the area, while of great economic importance, are only briefly 
mentioned in this report as they will be considered at length in Bulletin 
Xo. X, now in course of preparation by the Virginia Geological Survey. 

The field studies which form the basis of this report were made by 
the writer during June, July, and August, 1910, and July and part of 
August, 1911. 

Xo attempt has been made to evaluate individual mines or to determine 
whether they can be operated at a profit, as that is properly the work of 
the consulting mining engineer and geologist; but such basic problems as 
the origin and distribution of the ore deposits, and their probable variation 
in depth—problems which can not be solved by the examination of a single 
property, or without the expenditure of much time and effort—have been 
investigated as fully as conditions would permit. 

Acknowledgments .—The writer desires to thank Dr. Thomas L. 
Watson,' State Geologist, under whose supervision the work was done, for 
the privilege of studying the area, and for his valuable advice and kindly 
assistance in the preparation of this report. He also wishes to acknowledge 
the many kindnesses shown him by the different operators in the district, 
and by others who aided him in the field investigations. 

The topographic map of the gold belt in the James River basin (PI. I) 
is compiled from the Palmyra, Farmville, Buckingham, and Appomattox 
sheets of the United States Geological Survey, with corrections inserted 
by the writer. The traverse maps, used as a base for the detailed geologic 
work, were compiled chiefly from surveys made by the writer. Control 
for the detailed map of the gold belt on the north side of James River 
(PI. II) was furnished by the United States Geological Survey and the 
Chesapeake and Ohio Railroad, and for the Arvonia-Xew Canton map 
(Fig. 2) by the Chesapeake and Ohio Railroad. Other acknowledgments 
are made in the body of the report. 


2 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


CHAPTER I. 

GEOGRAPHY AND HISTORY. 

LOCATION. 

The district described in this report is situated a little east of the 
geographic center of the State, and lies on both sides of James lihei, 
about 60 miles above Richmond. It comprises the southeastern part of 
Fluvanna County, most of the western part of Goochland County, the 
northern three-fourths of Cumberland County, and adjacent portions of 
Buckingham, Powhatan, and Amelia counties, Virginia. The exact loca¬ 
tion is shown in the index map, fig. 1, and a large topographic and 
geologic map of the area is given on PI. I, which will be found in the 
pocket at the back of the book. 



The area is trapezoidal in shape, being 30 miles long in a north and 
south direction, with a width of 15 miles at the northern end and over 32 
miles along the southern boundary. It covers approximately 705 square 
miles. 

The greater portion of the district is easily accessible from stations on 
the various railroads that cross it. The Chesapeake and Ohio Railway, 
following the north bank of James River, crosses the north central portion 
of the area in an east and west direction, while the Buckingham Branch 
of the Chesapeake and Ohio and the Virginia Air Line railways approxi- 













GEOGRAPHY AND HISTORY. 


3 


mately parallel the western boundary, the former extending south from 
Bremo Bluff to Kosney, its terminus near the southern line, and the latter 
running from Strathmore northeast to Carysbrook and thence northward 
approximately parallel with Bivanna River. The Tidewater and Western 
Railway, a narrow gauge line, crosses the southeastern corner of the area. 

With reference to the major physiographic divisions of the State, the 
area is located in the center of the Piedmont Plateau; it lies within the 
belt of old crystalline rocks that extends from New Brunswick to Alabama; 
and is a part of the gold belt in the Southern Appalachians region. 

TOPOGRAPHY. 

The topographic features of the gold belt present little by way of 
variation; the land surface is gently rolling, consisting of broad flat- 
topped hills or ridges and narrow valleys. The ridges are remarkably 
uniform in elevation, ranging from 450 feet above sea level along the 
eastern border of the area, to 550 or 600 feet in the western portion, and 
the valleys of the larger streams have an average elevation of about 225 feet. 

The only variation in the monotony of the topography is furnished 
by Willis Mountain in the southwest corner of the area, which is the most 
prominent single feature of relief found in the State east of the outlying 
ranges of the Blue Ridge. It consists of a narrow ridge, about two miles 
long in a north and south direction, which rises abruptly from the Piedmont 
Plateau to a height of 1,159 feet above sea level, the upper portion being 
exceedingly precipitous and almost bare of vegetation. 

DRAINAGE. 

The area is drained by James River and its tributaries. James River 
flows directly across the area in a general easterly direction. Rivanna 
River and Byrd Creek are the principal streams entering James River on 
the north; and Slate River, Willis River, and Muddy Creek on the south. 
Appomattox River, flowing northeasterly, cuts across the southeast corner 
of the area and finally empties into the James below Richmond. Minor 
creeks and branches spread out from the principal streams, and completely 
drain all parts of the district. 

The estimated mean yearly discharge of James River at Cartersville, 
where the drainage area is 6,232 square miles, is 8,189 cubic feet per 
second. These figures are based on daily observations taken between 
January 1, 1899, and December 30, 1905, under the direction of the 
Hydrographic Branch of the United States Geological Survey.® During 

«Grover, N. C., and Bolster, R. H.. Hydrography of Virginia, Bull. No. Ill, Geol. 
Survey of Virginia, 1906, pp. 142-152. 



4 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


this period of seven years the maximum discharge for any single day was 
97,800 cubic feet per second on December 15, 1901, and the minimum 
discharge for any single day 842 cubic feet per second on September 15, 
1900. 

SOIL. 

The alluvial soils of the valleys, while limited in extent, are very rich; 
but the residual soils that cover the ridges are for the most part lean, and 
do not make first-class farming land. It was originally covered with a 
heavy growth of timber which has been greatly thinned out by cutting. 
All of the bottom lands and much of the uplands are at present under 
cultivation, but large areas of the latter have been allowed to grow up 
with a second growth of timber. While not naturally so rich as the 
bottom lands, much of this residual soil is capable, under proper farming 
methods, of a high degree of productivity. 

CLIMATE. 

The climate is equable and agreeable during the greater part of the 
year; the mean annual temperature is about 56° F., and the thermometer 
seldom drops as low as zero in the winter or reaches as high as 100° in the 
summer. The average yearly precipitation is about 42 inches, and this is 
quite evenly distributed throughout the year, so that prolonged droughts 
in summer or excessive rain and snow in winter are seldom experienced. 


CULTURE. 

The country is sparsely populated, and there are no large towns within 
the area. The chief industry of the inhabitants is farming, with corn 
and tobacco as the principal crops. Considerable lumbering is still carried 
on, and many railroad ties are shipped out of the district. Slate has 
been extensively quarried in Buckingham County for many years, and 
mining was at one time an important industry, but recently it has been 
carried on only in a spasmodic way. There are practically no manu¬ 
facturing industries in this section, and although there is good water¬ 
power in certain localities it has as yet received little attention. Many of 
the smaller streams have been utilized to run saw mills and grist mills 
for local custom, but this is the extent of water-power development. 
Within the past few years great strides have been made in the public 
school system, and large new school buildings have been erected in nearly 
all of the towns. 


GEOGRAPHY AND HISTORY. 


HISTORY. 

The early history of gold mining in the James River valley is so closely 
connected with the development of that industry elsewhere in Virginia, 
and indeed throughout the Southern Appalachians region, that a brief 
outline of the more important happenings in other parts of the gold belt 
will be given. The general history of the entire gold belt was summed 
up by J. D. Whitney® in 1854, and by Geo. F. Becker^ in 1895. 

According to Becker the first mention of gold in the Southern Appa¬ 
lachians states is by Herrera®, and “is to the effect that on June 4, 1513, 
while Ponce de Leon lay near the southern end of the peninsula of Florida, 
he was informed that a cacique in the neighborhood had a quantity of 
gold.” Several years later Spanish and French explorers refer to the 
possession of gold by the Indians; and Lemoyne, in his “Brevis 
Narratio”^, of the journey made by Laudonniere in 1564, describes a 
method used by the Indians in separating gold from sands, which they 
found in rivers flowing from the Appalachian Mountains. Authorities 
differ as to how the Indians obtained their gold, but it seems probable 
that no systematic efforts were made by them to recover the metal. It 
can scarcely be doubted, however, that they found gold nuggets and made 
use of them, for in later years white miners found many large nuggets 
on the surface, some weighing several pounds, and such lumps must have 
been more plentiful before the country was settled. While the Spaniards 
are reported to have done some mining in Georgia in the seventeenth 
century, practically no systematic work was undertaken until after the 
beginning of the nineteenth century. 

The earliest authentic reference to gold in Virginia is by Thomas 
Jefferson in 1782. He describes a lump of ore found on the north side 
of Rappahannock River about 4 miles below the falls. The gold “was 
interspersed in small specks through a lump of ore of about four pounds 
weight, which yielded seventeen pennyweight of gold of extraordinary 
ductility.” e 

In 1799, the Reed nugget was discovered in Cabarrus County, North 
Carolina, and some years later more lumps were found, one weighing 28 

aTlie Metallic Wealth of the United States, Philadelphia, 1854, pp. 114-134. 

bReconnoissance of the Gold Belt of the Southern Appalachians, 16th Ann. Rept. 
U. S. Geol. Survey, 1895, pt. Ill, pp. 253-258. 

cHerrera Dec. 1, Book IX, Chap. 5. 

^Published by De Bry in 1591. 

ejefferson, Thomas, Notes on the State of Virginia, 2d Am. ed., Philadelphia, 
Nov. 12, 1794, p. 32. 



6 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

pounds. Up to 1825 all the gold produced in North Carolina came from 
placer gravels, but during that year veins were opened in Montgomery 
County and afterwards in Mecklenburg County. Between the years 1804 
and 1828, all gold of domestic production deposited at the United States 
mint, amounting to only $116,000, came from North Carolina; but in 
1829 the mint records show a production of $2,500 from Virginia, and 
during the same year South Carolina sent gold worth $3,500 to the mint. 

In Virginia gold was discovered at very nearly the same time in both 
Orange and Goochland counties. Dr. Watson states that, “the Virginia 
Mining Company of New York, operating between the years 1831 and 
1834, the Grasty tract of land in Orange County, was the first gold mining 
company incorporated in Virginia. The date of the incorporation was 
March 10, 1832. The Orange County, Virginia, deed books show that 
a one-half interest in a 20-year lease on the 5-acre mining tract, dated 
1829, was purchased in 1831 for $30,000 in cash.”® 

The first discovery of gold in the James River basin was probably on 
the Collins place in Goochland County, about 1829. The first attempt 
at mining was by the Fishers, who built dams across the branch and 
prepared to work the gravels in rockers. Before active mining had 
actually begun, the property was turned over to Stevens Collins, who con¬ 
tinued to work the placers for several years, and the Fishers transferred 
their operations to Busby Branch, 1.5 miles southwest of Tabscott. The 
discovery of the gold-bearing veins at the Tellurium mine is said to have 
been made in 1832 by G. W. Fisher while hunting, and according to 
J. R. Hamilton, veins were found on the Waller property by John Moss 
during the same year. Discoveries on other properties in the district 
followed in rapid succession. When Prof. W. B. Rogers wrote his “Report 
of the Geological Reconnoissance of the State of Virginia, 1835,” Booker’s 
mine (the Morrow mine) was already under active development. The 
history of the different mines, so far as known, is given under the descrip¬ 
tion of individual properties in Chapter V. 

On most properties gold was found first in the branches, and as the 
placer gravels were frequently rich and could be worked by crude methods 
necessitating little or no capital, the deposits along the branches were 
rapidly exhausted. In most cases the mining was done by lessees, who 
paid a royalty of about 10 per cent, of the gold recovered. The first 
primitive washing was with the pan, but almost from the first rockers 
were used on the branch gravels. Long-toms were also used, and in a few 


aWatson, Thomas L., Mineral Resources of Virginia, Lynchburg, 1907, p. 549. 



GEOGRAPHY AND HISTORY. 


7 

places hydraulic mining was carried on, but most of the branches had 
insufficient grade to permit the use of sluice-boxes. 

The veins from which the placer gold was derived were frequently 
discovered in working up the branches, and as the placer gravels became 
exhausted, a close search was made for the primary deposits. When the 
veins were first found, many of them were worked in a very primitive 
fashion, the gold being recovered by the crudest mechanical processes. 
The high percentage of free gold, the great depth of residual decay, and 
the low cost of mining these ores, helped to make such methods profitable. 
Small shafts or pits were sunk on the outcrops where pannings of the 
surface soil indicated the presence of much gold. In the decomposed 
rock above water level blasting was not necessary, and in some places it 
was possible to sink nearly 100 feet through “picking ground.” The ore 
was usually raised by hand or sometimes with a horse-whim. 

At first the ore was crushed by hand in iron mortars after a preliminary 
hand sorting, and the gold obtained by panning, mercury being some¬ 
times used to amalgamate the gold. Crushing was also carried on in 
wooden mortars lined with iron, while the heavy pestles were attached to 
long sweeps operated by hand. At the Tellurium mine an arrastra driven 
by horse-power is said to have been employed for a short time, but was 
soon replaced by a stamp mill, or “pounding mill” as they were then 
called. According to Xitze and Wilkins this stamp mill was in operation 
as early as 1836, making it one of the first, if not the first, to be erected 
in this country. It had six wooden stamps, shod with iron, which weighed 
about 50 pounds each, and the ore was crushed on an iron die plate. The 
stamp stems were square and did not revolve as in later mills, for the 
cams worked in slots cut into the stems. 

At a later date larger and more efficient mills were installed, a 40- 
stamp mill being built by Commodore Stockton at the Tellurium mine as 
early as 1848, while a mill with 72 stamps was in operation at the Morrow 
mine, Buckingham County, in 1854. Tremain steam stamps, various 
types of rotary pulverizers, and a number of other mills have been tried 
with more or less success at different mines. 

As the water level was reached the rock became harder, rendering- 
blasting necessary, the water that was encountered had to be removed by 
pumping, and the sulphides, which began to replace the oxidized ores 
found at the surface, contained less free gold. It is also probable that the 
total gold content of the surface ores was higher than that of the sulphide 
ores, because of some enrichment through concentration of a part of the 


8 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


gold originally present in the eroded portions of the veins. All of these 
factors combined to make mining more expensive and the recovery of the 
gold more difficult, forcing most of the mines to cease operation after the 
ores above water level had been exhausted. This period in the develop¬ 
ment of many of the mines was approximately coincident with the out¬ 
break of the Civil War, which put a stop to practically all mining opera¬ 
tions both in Virginia and in the South generally. 

Since the close of the war there have been spasmodic attempts to 
reopen many of the mines, and while these efforts have been accompanied 
by varying degrees of success and failure, they have for various reasons 
always ended in the same way—the final cessation of all mining. Gold 
can he recovered from refractory sulphide ores, hut the methods of ex¬ 
traction are more complex and costly than the simple amalgamation 
processes that suffice for the oxidized ores near the surface. In the case 
of a producing mine, the introduction of auxiliary processes for the treat¬ 
ment of refractory ores necessitates an additional outlay of capital; but 
the metallurgical process now used had not been perfected when the 
exhaustion of free milling ores made the profitable handling of sulphide 
ores a necessity, if the mines were to remain open. It is much more costly 
to introduce new processes at old mines that have been long abandoned, 
for with the ores near the surface exhausted, prospecting is more difficult, 
and a larger amount of dead work must be carried out before pay ore can be 
developed. Most companies that have undertaken to reopen Virginia gold 
mines have done so with insufficient capital, and usually the men in charge 
of operations have lacked technical training. Mismanagement and igno¬ 
rance of the common principles of mining have resulted in the erection 
of expensive surface plants before the mines were developed to a point that 
would permit the making of adequate tests of the quality and probable 
quantity of the ore. 

The metallurgical processes which have elsewhere proved successful in 
recovering gold values from refractory ores, have usually included con¬ 
centration of the sulphides, and separate treatment of the concentrates 
and tailings. The concentrates are generally smelted with other ores, or 
treated by chlorination or cyanidation after a preliminary roasting, while 
the tailings are usually subjected to some variation of the cyanide process. 
In 1879, a Mears chlorination plant was erected at the Phoenix mine in 
North Carolina, under the management of Mr. A. Thies, who improved 
and developed it into what was later known as the Thies process. In 
1881, the Mears process is reported to have been tried at the Snead mine, 
but no details are given. An attempt to treat the sulphides at the Morrow 
mine by the Mears chlorination process, in 1893-94, is said to have failed 


GEOGRAPHY AND HISTORY. 


9 


because of mechanical defects in the process used, though a satisfactory 
extraction of the gold was obtained. 

According to Nitze and Wilkins a cyanide plant was in operation at 
the Gilmer (Young American) mine in 1893; with what success is not 
known. A preliminary test of the cyanide process, at the Bertha and Edith 
mine in 1897, is reported to have been successful, but the plant was 
destroyed by fire soon after completion and was not rebuilt. At the 
Hughes mine both concentrates and tailings were treated by the cyanide 
process, the sulphides being first roasted in a muffle furnace, and an 
extraction of over 90 per cent, is claimed. 

Recently there has been renewed activity in the district, a number of 
the old mines have been reopened, and some new development work done, 
but as yet none of the mines have gone much deeper than 100 feet below 
the surface. As the free milling ores above water level are now practically 
exhausted, future mining necessarily depends on the successful treatment 
of sulphide ores. 

PRODUCTION. 

The statistics of production during the years when gold mining was 
most active in Virginia, are not sufficiently detailed to make possible the 
compilation of data giving the production of individual mines, or of the 
district as a whole. The few figures that are available relate to particular 
mines, and are given under the descriptions of the different properties in 
Chapter V. The annual production of gold in the James River basin has 
probably varied with that of the State. After the first deposit of $2,500 
at the United States mint in 1829, the gold production of Virginia 
steadily increased until 1833, when it reached a value of $104,000. There¬ 
after it averaged about $56,000 yearly up to the outbreak of the Civil War, 
and since the war the production has ranged from a minimum of $2,024 
in 1884, to a maximum of $15,000 in 1906, averaging about $6,000. 

PREVIOUS GEOLOGIC WORK. 

No detailed geological work dealing with this or any other portion of 
the gold belt in Virginia has been published previous to this report. 
Since the first discovery of gold, the mines in the James River basin have 
been examined from time to time by geologists and mining engineers, 
and a number of reports on individual properties have been published. 
Some of the early American and English geologists, who visited the 
district, became interested in the genesis of the ore-bodies and advanced 
theories to explain their mode of formation; but at that time the petro¬ 
graphic microscope had not been developed, and the science of geology had 
not reached a stage permitting detailed geological study in an area of old 


10 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


metamorphic rocks. In more recent years the lack of accurate topographic 
maps, the depth of residual decay, and the absence of deep mines', have 
combined to discourage geologists from undertaking work in the district. 

Several studies treating of the gold belt in the Southern Appalachians 
region as a whole have been published, and in these the principal mines 
in the James River valley receive brief mention. A number of papers, 
usually brief in character and dealing chiefly with the economic and engi¬ 
neering phases of the properties, have appeared from time to time. In the 
Bibliography is given a list of the titles of all the principal papers which 
refer in any way to the gold veins in this district. A brief review of the 
more important conclusions developed by the different geologists that have 
worked in the area is outlined below. 

The first geological work, of which there is any record, was done by 
Prof. Wm. B. Rogers, who in 1835 published his “Report of the Geological 
Reconnoissance of the State of Virginia.'’ He mapped all of the rocks 
in the gold belt as primary, but states that the rocks lying to the west of 
the belt of gneiss “assume various intermediate characters, until at length 
the truly crystalline structure is lost, and numerous forms of slate of very 
peculiar and equivocal features make their appearance. At what precise 
points the rocks of unequivocally primary character terminate, future 
researches must ascertain.”® 

In describing the veins, Rogers points out that while in the main they 
conform to the inclination of the enclosing strata, this correspondence is 
far from exact, and that in places the veins divide, and the separated 
portions reunite or send off other branches. From this he concludes: 

“It would thus appear, that these numerous veins of quartz are not 
to be regarded as deposits coeval with the regularly stratified rocks among 
which they are found, since in that case their position and structure would 
exhibit a like degree of uniformity, but as matter which, subsequent to 
the production of the neighboring rocks, was forcibly injected between 
them by igneous agencies from beneath, rising in the directions of least 
resistance, and therefore, generally, though by no means uniformly, 
following the plains of stratification of the rocks through which they 
passed. Instead, therefore, of considering them as beds like the adjoining 
strata, as some writers have done, we would incline to class them among 
veins of injection, of which numerous instances occur in other parts of 
the globe. We are the more persuaded of the correctness of this view of 
their origin, from the consideration that throughout all the region in 
which the quartz veins are found, very peculiar modifications in the 
structure and composition of the surrounding rocks are invariably to be 
observed—modifications for which no adequate cause can be found in the 
other igneous rocks which occasionallv occur.” 6 

aRogers, Wm. B., A Reprint of the Geology of the Virginias, New York, 1884, 
p. 72. 

&Ibid., pp. 75-77. 



GEOGRAPHY AND HISTORY. 


11 


Prof. B. Silliman examined the Busby and Moss mines in 1836, and 
while in the district also visited the Tellurium mine. As a result of his 
observations he reached conclusions in regard to the nature of the veins 
which are at variance to those advanced by Prof. Eogers. He states that: 
“The auriferous or gold-bearing quartz of the gold region of Virginia 
(and, as far as I am informed, of the states farther south) forms, not 
strictly veins but rather beds or layers—in general not interfering with 
but conforming to the regular structure of the country.” 6 * 

Prof. Eogers, in his “Eeport of the Progress of the Geological Survey 
of the State of Virginia for the Year 1839,” describes the Triassic area 
lying in Prince Edward, Cumberland, and Buckingham counties under 
the name of “middle secondary formations,” 6 but maps the rest of the area 
embraced in the present report as “primary.” 

Prof. D. T. Ansted in 1854, after a careful study of the region, 
strongly opposed the theories of Eogers, both as to the genesis of the gold 
veins and in regard to the manner in which the Alleghanies were formed. 
Ansted points out the resemblance of many of the “so-called veins” to the 
quartzite exposed in the bluffs at New Canton and says: “It is not with¬ 
out importance that these hard sandstone bands pass into and alternate 
with quartz bands parallel to them, and that this quartz is hyaline, and 
has in all respects the aspect and general character of the auriferous veins 
of the adjacent districts.” 0 He further states that: 

“There were perhaps originally a multitude of beds, consisting of such 
materials as are still accumulating every day upon the earth. These beds 
were altered more or less by chemical agency, but while some still retain 
clear marks of their mechanical origin, others have become so far 
crystalline that the new arrangement of particles obliterated the old. 
That the syenites, greenstones, and gneissic rocks, as well as the chloritic 
schists, hornblendic schists, pale and blue slates, and other well-marked 
mechanical rocks, were once alternating aqueous deposits, there is no 
doubt in my mind; and I also believe that the gold as well as the iron 
was originally disseminated through the whole, and has been since re¬ 
arranged and collected into certain portions, whether veins or bands, by 
a process of segregation, which has also changed siliceous sands into the 
condition of alternating quartz bands.” 6 * 


«Silliman, B., Remarks on Some of the Gold Mines, and on Parts of the Gold 
Region of Virginia, Founded on Personal Observations Made in the Months of 
August and September, 1830, Amer. Jour. Sci. and Arts, 1837, vol. xxxii, pp. 98-130. 
&Ibid., pp. 322-323. 

cAnsted, D. T„ The Alleghanies and the Gold District of Eastern Virginia, 
Scenery, Science and Art, London, 1854, Chap. 3, p. 287. 
dAnsted, D. T., Op. cit., p. 292. 



12 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


Ansted described the Waller, London and Virginia, and Morrow veins, 
all of which were exposed at the time of his visit, and his descriptions 
show that he was a remarkably careful and accurate observer. 

Dr. H. Credner, during the latter part of 1865, made a detailed exam¬ 
ination of the gold deposits of Virginia and North Carolina, and the 
portion of his report relating to Virginia mines, which was published in 
1868-69, gives a comprehensive list of the gold-hearing properties in the 
James River basin. His conclusions in regard to the geology of the deposits 
are stated as follows: 

“The slate belt is of the highest technical interest, on account of the 
variety and multitude of mineral deposits which it encloses. Mineral- 
ogically it is made up of soft micaceous slates, siliceous slates poor in mica, 
chloritic, talcose, and roofing slates. All these varieties have an immediate 
connection with the analogous slate formation of North Carolina, which 
has been named by Emmons the Taconic system. We are therefore 
justified in describing this Virginia slate zone as belonging to this pre- 
Silurian oldest fossiliferous system. 

“Somewhat as the coal measures lie between carboniferous sandstones 
so between the layers of these slates lie parallel metalliferous intercala¬ 
tions, striking and dipping with the enclosing rocks and therefore not veins 
proper in a geological sense.”® 

In 1885, I. C. Russell made a reconnoissance of the Triassic (Newark) 
area lying in Prince Edward, Cumberland, and Buckingham counties, 
determining the presence of a fault along its eastern boundary north of 
Farmville, and several north and south faults in the central portion of 
the area. 6 

In 1892, N. Id. Darton announced the discovery of fossils in the slate 
of the Arvonia quarries, and the identification of these fossils by Walcott 
placed the slates in the upper Ordovician (Cincinnatian).® 

In 1911, Thomas L. Watson and S. L. Powell correlated the Arvonia 
slate belt with the Quantieo slate belt in Prince William, Stafford, and 
Spottsylvania counties, Virginia, and described the occurrence of tuff- 
aceous beds and metamorphosed rhyolite interbedded with the slates in 
each district. d 


«Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour, of Mining, 1868, vol. vi, p. 361. 

^Russell, I. C., The Newark System, U. S. Geol. Survey, Bull. No. 85, 1892, 
pp. 88-89. 

cDarton, N. H., Fossils in the “Archaean” Rocks of Central Piedmont, Virginia, 
Amer. Jour. Sci., 1892, vol. xliv, pp. 50-52. 

JWatson, Thomas L., and Powell, S. L., Fossil Evidence of the Age of the 
Virginia Piedmont Slates, Amer. Jour. Sci., 1911, vol. xxxi. pp. 33-44. 



CHAPTER II. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 

INTRODUCTION. 

The results of the areal survey of the gold belt in the James River 
basin are shown on the geological maps, Pis. I and II, and figs. 2 and 17. 
Owing to the lack of sufficient exposures it is not possible to map all of 
the region in equal detail. Plate I is a topographic and geologic map of 
the entire area, on which only the principal formations are differentiated. 
The northwestern portion is occupied chiefly by pre-Cambrian schists, 
quartzites, and gneisses of sedimentary origin, and the southeastern por¬ 
tion, by more or less gneissic igneous rocks of the granite-diorite family. 
The northern end of the Farmville area of Triassic rocks crosses the 
southern boundary and occupies a small area between Ca Ira and Willis 
Mountain. 

A narrow belt of Ordovician rocks extends in a southwesterly direction 
from a point on Long Island Creek, between Palmyra and Wilmington, 
nearly to Alpha in Buckingham County, a distance of about 22 miles. Its 
boundaries are shown on the smaller detailed maps but not on PI. I. A 
large scale map of the entire slate belt will be published shortly in con¬ 
nection with a report on the slate deposits of Virginia, now in preparation 
by the State Geological Survey. 

Most of the gold mines are situated in the northeastern portion of the 
district shown on PI. I, and this section is given in greater detail on PI. II. 
Figure 2 is a detailed geological map of the region around New Canton 
and Arvonia, Buckingham County, showing the distribution of the Ordo¬ 
vician rocks, and the relation of the New Canton copper mines to the 
contact between the pre-Cambrian schists and intrusive granite. 

All of the rocks in the area mapped, except the Triassic sediments, 
have been extensively altered by regional dynamic metamorphism, the 
degree of alteration being most intense in the pre-Cambrian rocks. In 
the following detailed descriptions the rocks are divided into two classes, 
namely, those that are sedimentary in origin and those that are igneous 
in origin; and the subdivisions of the two classes are based, so far as 
possible, on relative age. 


14 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


ROCKS SEDIMENTARY IN ORIGIN. 

GENERAL CLASSIFICATION. 

The rocks of sedimentary origin, described in this report, may be 
divided for purposes of mapping and description into three main groups— 
pre-Cambrian, Ordovician, and Triassic—which are separated from one 
another by great unconformities. These groups will be discussed in the 
order given, which is that of relative age. 

The pre-Cambrian rocks are the oldest in the district and have been 
extensively altered by dynamic regional metamorphism and by the intru¬ 
sion of large masses of igneous rocks. In many instances they have been 
so completely metamorphosed that it is difficult or impossible to discover 
the character of the original sediments. Tor the most part these rocks 
have a fairly uniform strike in a northeast and southwest direction, and 
dip toward the east at angles varying from 45 to 90 degrees. 

The Ordovician sediments are next in age to the pre-Cambrian rocks, 
but are separated from them by a long time interval, and are much less 
metamorphosed. The beds of this formation have been extensively folded 
and faulted, and while they mostly dip at steep angles, there is not the 
same uniformity in this respect as in the older sediments; the dip of the 
Ordovician beds changes suddenly within short distances, while the pre- 
Cambrian rocks are nearly isoclinal in dip. 

The Triassic sediments constitute the youngest formation of the area, 
unless the recent alluvium, deposited in the larger valleys, is taken into 
consideration. The Triassic rocks have not been subjected to the crustal 
movements which have metamorphosed the older rocks, and since they 
have never been deeply buried, they are only partly consolidated. The beds 
dip gently in various directions and have been only slightly disturbed by 
minor faulting. 

PRE-CAMBRIAN. 

General Statement. 

In the absence of direct fossil evidence, the correlation of the rocks 
which have been mapped as pre-Cambrian must rest entirely on lithologic 
and structural grounds. It is known that the Proterozoic era in North 
America was brought to a close by great crustal movements, and wherever 
the rocks belonging to this period have been observed in the Piedmont 
region, they show the effects of intense dynamic metamorphism. The chief 
evidence of the pre-Cambrian age of the older rocks, in the area under 
consideration, is furnished by their relatively high degree of crystallinity 


DESCBIPTIVE GEOLOGY AND PETROGRAPHY. 


15 


and extremely schistose structure as compared with the rocks a short 
distance to the west, which are believed to be Cambrian in age. (See 
Geological Map of Virginia.®) 

The great age of these rocks is also evidenced by the long period of 
time intervening between their formation and the deposition of the Arvonia 
slates, upper Ordovician (Cincinnatian) in age, which are the oldest rocks 
in the area known to be fossil-bearing. After the pre-Cambrian sediments 
were laid down, they underwent the profound changes which resulted in 
their metamorphism ; they were intruded by great masses of igneous rocks; 
and finally, sufficient time elapsed for erosion to remove a large amount 
of overlying material, and expose the intrusive granite and other rocks of 
the anamorphic zone; and all of this happened prior to the deposition of 
the Ordovician sediments. 

The subdivisions of the pre-Cambrian series in this district must be 
based, in the absence of fossils, entirely on lithologic grounds. It is not 
even possible to state definitely which beds were laid down first or which 
were laid down last. The rocks have all been extensively altered by regional 
metamorphism and are entirely crystalline, so that it is frequently difficult 
to determine their original character; and in some instances, especially in 
the vicinity of later intrusives, it is impossible to distinguish between those 
that are igneous and those that are sedimentary in origin. The principal 
rock types are quartzites, schists, and gneisses, varying in texture and 
mineral composition; and rocks occur that are intermediate between the 
more important varieties. In fact nearly all gradations exist between the 
different extremes in mineral composition. 

Quartzite. 

GENERAL CHARACTER AND DISTRIBUTION. 

Quartzites are fine-grained, siliceous rocks, originally deposited as beds 
of sand and later firmly cemented through metamorphic agencies. Some 
of the pre-Cambrian quartzites in this area are very pure, consisting almost 
exclusively of quartz, but usually there is more or less mica and chlorite 
present in small flakes, and with increase of these minerals the rocks grade 
into mica schists. In places the quartzites are highly ferruginous, con¬ 
taining considerable percentages of hematite and magnetite, and at several 
localities the iron content is so high that the beds have been prospected for 

aWatson, Thomas L., Geological Map of Virginia, Virginia Geological Survey, 

1911. 



16 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

iron ore. The quartzites also contain variable but usually unimportant 
amounts of feldspar, small inclusions of zircon, ilmenite, and rutile 
needles; and near igneous contacts, such minerals as garnet, hornblende, 
sillimanite, and cyanite are occasionally present in the impure varieties. 

Since they are strongly resistant to erosion, the quartzites commonly 
outcrop along the ridges, and in places where the larger streams cut 
through such ridges the valleys are narrower, being frequently enclosed by 
cliff-like bluffs, while rapids are present in the channels. The residual 
soils resulting from the disintegration of the quartzites are sandy and 
infertile. 

Most of the quartzite beds are less than 20 feet in thickness but some 
of them measure over 200 feet. They are frequently lenticular in shape, 
pinching out along the strike and dip, though some of the more persistent 
beds can be traced for a distance of several miles. The quartzites are the 
most widely distributed of all the rocks in the pre-Cambrian series of 
altered sedimentaries, yet, owing to the high inclination of these beds they 
do not form extensive areal formations. 

The beds of quartzite are commonly mistaken for quartz veins and 
much money has been wasted in sinking pits to prospect them for gold. 

DETAILS OF OCCURRENCES. 

Bremo Bluff .—The most prominent exposures of quartzite occur on 
either side of James River just above the railroad station at Bremo Bluff. 
Here within a distance of half a mile there are a number of beds, ranging 
up to 200 feet and over in thickness, which are interbedded with fine¬ 
grained schists, the strike of the formations being about N. 20° E., and 
the dip 80° to 90° east. The largest beds of quartzite outcrop near the 
Bremo bridge over Janies River, and in passing westward they become 
successively thinner and more impure until they entirely disappear. 

Because of their great resistance to erosion the larger beds of quartzite 
form a ridge, having an elevation of about 150 feet above the floor of the 
valley; and where this ridge is cut through by the river, it terminates in 
abrupt cliffs (see PI. Ill, figs. 2 and 3), and the valley is much narrower 
than it is a short distance above and below (see map, fig. 2). The ledges 
of quartzite outcrop in the bed of the river, causing the rapids shown in 
PI. Ill, figs. 1 and 2. The piers supporting Bremo bridge are built on 
one of these outcrops. 



cz 


& 

a. 

£ 

I 

o 


be 

jo 

c 

a? 


be 




























































































































































































































18 


GEOLOGY OF THE GOLD BELT IX THE JAMES E1VER BASIN. 


The quartzite is a fine-grained, close-textured rock, light gray in color 
when fresh, turning to light brown upon weathering, and where purest is 
nearly massive. The crustal movements, which have intensely meta¬ 
morphosed the softer rocks with which they are interbedded, have scarcely 
affected the quartzites. Close inspection, however, shows a slight schis- 
tosity parallel to the bedding, and this becomes more conspicuous where 
the rocks are less pure. Fine flakes of sericite, chlorite, and biotite, and 
more rarely a little magnetite, pyrite, and garnet are the principal mineral 
impurities that may be detected megascopically. 

In places the quartzites contain numerous small angular cavities 
arranged in bands or zones parallel to the bedding, and some of these are 
filled with calc-ite. The shape and distribution of these holes suggests 
that they may be due to fossils, possibly brachiopods, but if so they are so 
badly distorted as to make identification impossible. Quartz veinlets, 
averaging less than an inch in thickness, occasionally cut the quartzite, 
and some of the veinlets contain calcite. 

Examined in thin sections under the microscope, the quartzite (Spec. 
452)“ consists chiefly of small grains of quartz, nearly uniform in size, 
which fit closely together as in a mosaic. Dust-like inclusions are plenti¬ 
ful, especially near the border portions of the grains. The quartzite has 
evidently undergone considerable recrystallization, with possibly some en¬ 
largement of the original grains by the addition of quartz in parallel 
orientation; and the border inclusions probably represent iron oxide and 
other interstitial material which has become incorporated in the enlarged 
grains. Garnet occurs in small, irregular grains which are much fractured 
and partly altered to chlorite. Numerous small flakes' of sericite are 
present, probably derived chiefly from argillaceous material, and there is 
also a little plagioclase and orthoelase feldspar, some of which shows 
partial alteration to sericite. Chlorite occurs in small, dark green flakes, 
and other minor accessories are biotite, light brown to green in color, a 
few small grains of magnetite and pyrite, and minute, colorless inclusions 
of zircon. The quartz shows very little optical distortion, possibly because 
of the extensive recrystallization. 

Tellurium mine .—The so-called “Big Sandstone” vein, at the Tel¬ 
lurium mine, is a bed of quartzite cut by gold-bearing veinlets and slightly 
mineralized by the vein-forming solutions. This bed of quartzite varies 
up to 6 feet or more in thickness and can be traced for a distance of 3 

aTlie numbers placed in parenthesis refer to field specimens and microscopic 
tliin-sections, which are on file at the office of the Virginia Geological Survey. 



X lj-rY X 1 i II 





Fig. .'5.—Nearer view of quartzite cliffs on north side of James River. Bremo Bluff. 


up James River from Bremo bridge. Rapids due to quartzite beds 


Fig. 2.—Quartzite cliffs near north end of bridge. Looking northeast. 


Fig. 1.—Looking 


PRE-CAMBRTAN QUARTZITE AT BREMO BLUFF. 










DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


ID 


miles or more along its line of strike. The rock is white to light gray in 
color, when fresh, with a slightly pinkish tinge on weathering. It is quite 
free from impurities other than sericite, which is the only accessory 
mineral that can be distinguished with the naked eye. For a detailed 
microscopic description of this rock see pages 161-163. 

London and Virginia mine .—At the London and Virginia mine there 
is a similar bed of quartzite, which in places is heavily impregnated with 
pyrite and more or less gold. This bed of quartzite ranges up to 20 feet 
or more in thickness, and the series of outcrops and prospect pits located 
along its line of strike indicate that it is practically continuous for a 
distance of 10 or 12 miles. Specimens of this quartzite from the London 
and Virginia and the Bondurant mines are described on pages 189 and 
193-194, respectively. 

Ferruginous Quartzite. 

GENERAL CHARACTER AND DISTRIBUTION. 

The ferruginous quartzites consist essentially of quartz, hematite, and 
magnetite. These three principal constituents vary greatly in their rela¬ 
tive proportions, but quartz is usually dominant, though locally the iron 
oxides may constitute 80 or 90 per cent, of the mass. Some of the iron¬ 
bearing quartzites contain a little sericite and biotite, and with the increase 
of these minerals the rocks pass into ferruginous schists. 

The ferruginous quartzites are of more frequent occurrence than the 
pure quartzites, and are found interbedded with the other sedimentary 
rocks in almost every portion of the pre-Cambrian area. 

DETAILS OF OCCURRENCES. 

Webb tract .—On the Webb tract, about three-quarters of a mile south¬ 
west of Lantana, a bed of ferruginous quartzite has been prospected for 
iron, and is exposed in several surface pits that have been sunk. The bed 
is over 6 feet in thickness, has an approximate strike of N. 45° E., and 
dips southeast at an angle of about 25°. It is interbedded with arkosic- 
gneisses, quartz-sericite schists, and other beds of quartzite. 

The rock is fine-grained, even-granular, and, when fresh, is brownish- 
gray in color, turning to dark brown or black on weathering. It is com¬ 
posed essentially of quartz, specular hematite, and magnetite, but a little 
sericite may sometimes be recognized with the aid of a lens. It is slightly 
gneissic in structure, because of some recrystallization, accompanied by a 
partial segregation of the quartz and iron ores into narrow bands parallel 


20 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


to the bedding and schistosity. The magnetite in these segregated bands 
or layers, which are usually 3 mm. or less in thickness, is somewhat coarser 
than that in the rest of the rock. 

The quartzite is cut by numerous irregular quartz stringers, ranging 
up to 3 or 4 inches in width, and, for the most part, conforming to the 
strike of the enclosing rock. These quartz veinlets in places contain plates 
of micaceous hematite. ISTear the veinlets the quartzite seems to have been 
leached of some of its iron content. 

Examined in thin section (Spec. 95) under the microscope, the 
quartzite shows a slightly schistose structure due to the partial arrange¬ 
ment of the iron ores in parallel lines. The quartz grains average about 
0.25 mm. in diameter, and fit closely together, interlocking almost per¬ 
fectly, but there is no evidence of granulation or optical distortion. The 
quartz individuals contain numerous small, dark red crystals of martite, 
the isometric form of hematite, which usually occur in well-formed octa¬ 
hedrons and are probably secondary (pseudomorphous) after magnetite. 
The larger masses of iron oxide are present between the quartz grains, 
and are frequently arranged in irregular, broken lines. Occasional hex¬ 
agonal outlines show that a large proportion of the oxide is hematite, but 
much magnetite is also present. The fact that the quartz individuals in 
immediate contact wh these larger masses of iron ore are practically free 
from the small inclusion 5 ?, indicates that both the quartz and the iron 
ores have undergone recrystallization, accompanied by a partial segrega¬ 
tion of the latter into larger masses. In places the iron ores are partly 
altered to limonite, and the boundaries between the quartz grains fre¬ 
quently show limonite staining. Considerable garnet (probably chiefly 
spessartite) is present, usually occurring as an interstitial filling between 
the quartz grains, and frequently along the contact between quartz and 
the iron ores. It is evidently secondary in origin, and, in some instances, 
appears to have partly replaced the quartz. The garnets are usually full 
of small dust-like inclusions, and more or less stained with limonite. 
Small, light green to colorless inclusions of zircon are common but not 
abundant. 

The Ayre tract .—On the Ayre tract, 3.5 miles east of Dillwyn, a large 
bed of ferruginous quartzite has been extensively prospected for iron ore 
by several shafts and open cuts. One of the shafts is 40 or 50 feet deep, 
t|ie others being somewhat less. 

The quartzite outcrops boldly, in places standing 6 to 8 feet above the 
surrounding surface, and along most of its course follows the crest of a 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


21 


ridge. The outcrops vary in width up to 200 feet or more, and the bed 
can be traced for over half a mile in a direction about 1ST. 45° E. 

The rock is essentially the same, both megascopically and microscopic¬ 
ally, as that described above. Some of it is slightly coarser grained, and 
octahedral crystals of magnetite 0.5 mm. in diameter can be distinguished 
in hand specimens. Sericite is sparingly present. 

Spessartite is occasionally present in the quartzite, occurring in ir¬ 
regular and more or less angular masses that range up to a foot or more 
in diameter. These masses are reddish-brown in color, with a waxy luster, 
and the weathered surface shows irregular, hackly cracks. Under the 
microscope (Spec. 420) the garnet is even-textured with few fractures 
and is seen to be full of extremely small inclusions. A few scattered 
grains of hematite are present, and with them there is often associated a 
little chlorite in fine, green shreds. The garnet is more or less stained 
by limonite. 

The quartzite is cut by numerous stringers of vein quartz, frequently 
containing prisms of black tourmaline; and one specimen was found in 
which radiating clusters of tourmaline had penetrated the quartzite to a 
depth of about 0.5 cm. A large amount of tourmaline is present on the 
surface near the outcrops. A number of other occurrences of iron-bearing 
quartzite are reported southwest of this locality, in the vicinity of Willis 
Mountain. 

The Scotia mine .—On the Scotia, mining property, a bed of ferruginous 
quartzite, known as the Hodges vein, has been prospected for gold. The 
quartzite is cut by a number of small, gold-bearing veinlets, and has been 
slightly mineralized by the vein-forming solutions; otherwise it is identical 
with the other ferruginous quartzites of the district. The development 
work that has been carried out is sufficient to expose the marked lenticular 
shape of the deposit (see fig. 16, p. 171). A megascopic and microscopic 
description of the rock is given on pages 171-172. 

Oilier localities .—Ferruginous quartzites occur at numerous other 
localities within the area mapped and thin sections from a number of 
them have been studied under the microscope, but as all of these arc 
essentially the same, they will not be described in detail. At Cassell's 
mine 2 miles northeast of Caledonia a bed of iron-bearing quartzite 8 feet 
or more in thickness has been prospected by a surface pit. The rock ex¬ 
posed seems to have undergone greater recrystallization than most of the 
similar deposits in the area. It is described in detail on pages 174-175. 

Ferruginous quartzite outcrops along the road three-quarters of a mile 
south of Stage Junction, where the bed has a strike of about X. 20° E. 


22 


GEOLOGY OF THE GOLD BELT IN THE JAMES LIVER BASIN. 


Another occurrence is located on the road from Stage Junction to Pryors 
Crossroads, at a point three-quarters of a mile northeast of Big Byrd 
Creek. Outcrops also occur near the road between Palmyra and Wilm¬ 
ington, at Fork Union, and at several points in the vicinity of the Hughes 
mine. At the last-named locality some of the specimens have the appear¬ 
ance of hematite breccias recemented with magnetite and hematite. 

Garnetiferous Quartzites. 

GENERAL CHARACTER AND DISTRIBUTION. 

Garnetiferous quartzites occur at several places in the district and are 
believed to be due to the metamorphic action of igneous intrusive rocks on 
impure quartzites. Chemical tests prove that the garnets are the iron- 
aluminum variety known as almandite. Sillimanite and sometimes a little 
cyanite are also present in association with the garnet. These rocks 
usually contain more or less hematite, magnetite, and seric-ite, and pass 
by gradation into the schists with which they are interbedded. 

This type of rock has a limited distribution and was found only in the 
vicinity of contacts between the pre-Cambrian sediments and the intru¬ 
sive granite. 

DETAILS OF OCCURRENCES. 

Lantana .—A bed of garnetiferous quartzite outcrops at Lantana, and 
for a mile southwest of the postoffice the road to Columbia follows approx¬ 
imately along the strike of this bed. It was traced in a northeast and 
southwest direction for a total distance of about 4 miles. The bed is 
probably not more than 10 or 15 feet thick and is usually much thinner. 

The rock is banded in light and dark layers which range up to 2 or 3 
inches in thickness. These layers are parallel to the bedding, the dark 
ones being composed largely of garnets while the light ones are chiefly of 
quartz. Radiating needles of sillimanite are common in places, and a 
little cyanite was identified. The garnets are dark red to brown in color, 
ranging up to about 0.5 cm. in diameter, but show very poor crystal form. 
Under the microscope (Spec. 96) they are seen to be full of small inclu¬ 
sions consisting of quartz and oxide of iron. These inclusions are 
elongated and arranged in lines approximately parallel to the bedding. 
The garnets are much fractured, and are stained by limonite which also 
coats many of the quartz grains. The quartz shows evidence of consider¬ 
able optical distortion and of extensive recrystallization. Xear the garnets 
the grains of quartz are sometimes arranged in bands that pass 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


23 


around these crystals. There are a few flakes of sericite present, and the 
only other constituent noted was a soft white mineral that occurred as a 
coating and filled small cavities. It is probably some form of amorphous 
silica. 

Weathered specimens of this rock often exhibit a hard surface crust 
having a rich reddish-brown color due to the presence of hematite, the iron 
of which has been leached from the partly decomposed minerals within, 
and reprecipitated near the surface. 

The quartzite is interbedded with and grades into a fine-grained quartz- 
sericite schist. 

Stage Junction .—A bed of garnetiferous quartzite outcrops in the road 
about half a mile northeast of Stage Junction. It is more schistose than 
the rock near Lantana, but is otherwise the same. 

Hornblende-Bearing Quartzites. 

Quartzites containing a few crystals of dark green hornblende occur 
at several localities close to the contact with the large area of intrusive 
granite, but they are of very limited distribution and therefore unimpor¬ 
tant. The rocks placed in this classification are intermediate between the 
normal quartzites and the hornblende schists. 

On the Columbia-Lantana road, three-quarters of a mile west of the 
bridge over Big Byrd Creek, there is an outcrop of hornblende-bearing 
quartzite. The rock contains blade-like crystals of hornblende, dark green 
to black in color, and ranging up to 3 mm. in diameter, which are em¬ 
bedded in an even-granular ground-mass of quartz with a few scattered 
crystals of garnet and sillimanite. A similar rock was found at the 
Margaret mine near New Canton (see p. 250). 

A fine-grained quartzite containing scattered prismatic crystals of 
dark green hornblende is exposed on the east side of Randolph Creek, 
where it is crossed by the road running from Lawford to Gold Hill. A 
similar rock was noted near Hatcher Creek about 3 miles west of Hatcher. 

Quartz-Sericite Schist. 

GENERAL CHARACTER AND DISTRIBUTION. 

Schists composed essentially of quartz and sericite in varying propor¬ 
tions are of common occurrence in all portions of the pre-Cambrian series 
of sedimentary rocks, and constitute one of the most important rock types 
of the area. In texture these schists range from fine to medium coarse- 


24 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

grained, and in composition from sericite-bearing quartzites to rocks in 
which the mica is dominant. The finer grained varieties, containing much 
sericite, were described by the early geologists under the name of talcose 
schists. The coarser varieties, in which quartz is dominant, are very 
resistant to erosion and therefore frequently form the ridges and other 
higher elevations, outcropping with considerable prominence. The quartz- 
sericite schists pass by gradation into the sericite-bearing gneisses, cyanite 
schists, and the ferruginous as well as the pure quartzites. Nearly all the 
schists found in this region contain more or less sericite, and there are 
numerous rocks intermediate in mineral composition between the quartz- 
sericite schists and most of the principal varieties. 

GENESIS. 

The positive evidence of bedding and the gradation of the quartz- 
sericite schists into rocks, such as the quartzites, which are necessarily 
sedimentary in origin, leave no doubt as to the manner in which the 
schists were originally formed. The beds were probably laid down in 
shallow waters near the shore, partly in the form of quartz-feldspar sands 
and argillaceous sands, and partly in the form of finer sediments, possibly 
white clays. The present character of the rocks is due to their alteration 
vinder dynamic conditions in the zone of anamorphism, and certainly in 
some cases the change has been aided by the intrusion of the large granite 
magmas. 

DETAILS OF OCCURRENCES. 

Big Byrd Creek .—On the east bank of Big Byrd Creek, three- 
quarters of a mile south of Bowles’ bridge, and 114 miles east of Stage 
Junction, there is an exposure of quartz-sericite schist in which the 
ratio of quartz to sericite is so great that it is almost a quartzite. The 
rock (Spec. 33) is fine-grained and white to light yellow in color when 
not stained pink and red by oxides of iron. It is highly laminated parallel 
to the schistosity, showing well-marked layers which are slightly folded 
and crumpled. The minerals distinguishable under the microscope are 
quartz, sericite, a little feldspar, and occasional inclusions of zircon. The 
quartz grains fit closely together and show little optical distortion. The 
feldspars are chiefly acid plagioclase and in places they show partial alter¬ 
ation to sericite. Most of the mica flakes are perfectly oriented parallel 
to the schistosity. 

Lantana .—For a distance of 500 or 600 yards southeast of Lantana the 
road passes across a belt of quartz-sericite schist, and this belt may be traced 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


25 


for 4 or 5 miles along its line of strike in a northeast and southwest 
direction, but in places it contains interbedded lenses of quartzite and 
other rocks. The schist (Spec. 42) is white to light gray in color, where 
not stained with iron, and usually fine-grained. Quartz is dominant over 
sericite, the flakes of which are all oriented parallel to the schistosity, so 
that when the rock is examined on surfaces at right angles to the cleavage 
it has the appearance of a quartzite rather than a schist. It is slightly 
banded, due to variation in the relative proportion of the quartz and 
sericite, and the layers show minor crumpling and folding. 

A specimen (100) obtained from an outcrop 2^4 miles northeast of 
Lantana, upon examination in thin section under the microscope, shows 
a little orthoclase and acid plagioclase feldspar, and occasional fluid 
inclusions and rutile needles. The feldspars show partial alteration to 
sericite and are much kaolinized. 

About a mile northeast of Lantana occurs a rock which is intermediate 
in composition between the quartz-sericite schists and the ferruginous 
quartzites. It is a fine-grained schist, bluish-gray in color, in which few 
of the minerals can be distinguished by the naked eye. In thin section 
(Spec. 89) under the microscope it is seen to consist essentially of quartz, 
hematite, and sericite, with a few scattered crystals of nearly colorless 
amphibole and possibly a little cyanite. The quartz grains are irregular 
in shape, fit closely together, and show some optical distortion. The 
hematite is chiefly of the micaceous variety. 

New Canton-Dillwyn road .—There are numerous outcrops of quartz- 
sericite schist along the ridge road leading from Hew Canton to Dillwyn. 
This rock is slightly coarser grained than the schists previously described, 
and the schistosity usually has a crinkled or corrugated appearance. It is 
light greenish-gray to white in color, where not stained various shades of 
pink by iron oxides, and is composed essentially of quartz and white mica, 
with a small amount of light green chlorite, and occasional specks of 
specular hematite. It is very resistant to erosion and therefore outcrops 
prominently and forms the watershed between the streams flowing into 
Hunts Creek and Slate River, and those flowing into Phelps Creek and 
Willis River. Locally the schist is called mountain rock, because of its 
occurrence along the summits of the higher ridges. 

A similar rock outcrops on Tower Hill, 2% miles south of Alpha and 
3 y 2 miles east-northeast of Dillwyn, and also on the slopes of Willis 
Mountain. 

London and Virginia mine .—A fine-grained quartz-sericite schist is 
exposed at the London and Virginia mine and at the other mines that 


26 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

have been opened along the strike of the same vein. In this rock the per¬ 
centage of sericite is high and is possibly dominant over the quartz. The 
schist, as well as the quartzite with which it is interbedded, has in places 
been heavily impregnated with pyrite. A detailed megascopic and 
microscopic description of the rock is given on page 186. A similar rock 
occurs in the mines near Hew Canton, and is especially prominent at the 
Hudgins mine (see p. 256). 

Bondurant mine .—A quartz-sericite schist, which was found on the 
dump at the Bondurant mine, contains small lenticular eyes of light-blue 
opalescent quartz. This variety of the schist is similar to the hand speci¬ 
men (211) obtained from the Scotia mine and described on page 170. 

Other localities. —Quartz-sericite schist is present along the road 3 
miles northwest of Ca Ira and parallels the contact with the granitic rocks 
on the east for a distance of several miles in a northeast and southwest 
direction. It occurs in the road 2 miles south of Kent’s Store, and also a 
quarter of a mile northeast of Byrd Creek on the road between Stage 
Junction and Pryors Crossroads; it outcrops on Byrd Creek, 1*4 miles 
north of Grays Mill, and in the road three-quarters of a mile south of 
Carysbrook; and it was noted along the road l^/o miles south of Gravel 
Hill. There are numerous other occurrences in the area, but these are 
sufficient to show the wide distribution of this rock type. 

Cyanite Schists. 

GENERAL CHARACTER AND DISTRIBUTION. 

The cyanite schists are composed chiefly of quartz, cyanite, and sericite 
or muscovite, and the relative proportions of these constituents vary 
within wide limits. There are all gradation from a rock composed almost 
entirely of cyanite, to one composed chiefly of coarse-grained quartz with 
only scattered prisms of cyanite; and these schists pass by gradation into 
quartz-sericite schists in which cyanite is sparingly present or entirely 
absent. Cyanite is also present in some of the gneisses that have been 
intensely metamorphosed (see pp. 133 and 136-138). 

The distribution of these schists is very limited and only two 
occurrences are known within the limits of the area mapped—one at 
Willis Mountain, and the other on the Trent farm, 3 y 2 miles southeast 
of Gravel Hill and 3 miles southwest of Hatcher. Similar schists have 
been described from the northwest corner of Charlotte County, about 25 
miles southwest of Willis Mountain, and it is interesting to note that in 
each instance rutile is a prominent minor constituent.® 

aWatson, Thomas L., and Watkins, J . H., Association of Rutile and Cyanite 
from a New Locality, Amer. Jour. Sci., 1911, vol. xxxii, pp. 195-201. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


27 


While cyanite is softer than most rock-forming minerals, it is almost 
unalterable, and therefore the cyanite schists are extremely resistant to 
the agents of decomposition, and outcrop boldly at each of the localities 
in this section. 

GENESIS. 

The structural relations of the cyanite schists, wherever observed, are 
indicative of a sedimentary origin, and, moreover, cyanite is not known to 
occur as a pyrogenetic mineral. The chemical composition of these schists, 
consisting chiefly of alumina and silica, suggests that they must have been 
derived from kaolin or very argillaceous sediments, and this view is sup¬ 
ported by the unusually high titanium content. Van Hise has called 
attention to the concentration of titanium in shales and other fine-grained 
sedimentary rocks.® The metamorphic minerals composing these schists 
were produced in the anamorphic zone under conditions of dynamic 
regional metamorphism, but the location of both occurrences, not far from 
large areas of intrusive granites, suggests that contact action may have 
been an influential factor in bringing about the alterations. Evidence in 
favor of the latter hypothesis is furnished by the variation in the character 
of the schist in the vicinity of a peculiar diorite dike, which occurs on the 
southern slope of Willis Mountain, and by the great abundance of tourma¬ 
line, chiefly in association with vein quartz, found near the base of the 
mountain. The absence of cyanite, sillimanite, and similar minerals from 
most of the contact rocks is probably due to the presence of iron, mag¬ 
nesium, and the alkalies, which have resulted in the formation of 
amphibole and mica rather than the pure aluminum silicates. 

DETAILS OF OCCURRENCES. 

Willis Mountain .—The topographical features of Willis Mountain are 
described on pages 89-91, the formation of the narrow ridge being attributed 
to the structural and lithologic character of the bed of cyanite schist 
which outcrops along the summit. This rock was described under the 
name of “kyanitic gneiss” by Rogers, who states that it “differs from all 
in its vicinity, and appears to have been elevated from below through the 
surrounding slates ;” b but the present writer saw nothing to indicate that 
faulting has been a factor in the formation of the mountain. The rocks 

aVan Hise, C. R., A Treatise on Metamorphism, Mono, xlvii, U. S. Geol. Survey, 

1904, pp. 974-975. 

^Rogers, W. B., Geologv of the Virginias, 1884, pp. 314-315. (See also pp. 71-72 
and 290-291.) 



28 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

that constitute Willis Mountain offer greater resistance to erosion than 
any of the other rock types found in this region, and the gradual erosion 
of the softer rocks has left this ridge standing as a monadnock high above 
the level of the Piedmont peneplain. The rugged and cliff-like nature of 
the outcrops near the summit of the mountain is shown in PL IV, fig. 1. 

The cyanite schist of Willis Mountain varies in texture according to 
the relative proportions of the two principal constituents—quartz and 
cyanite—and passes by gradation into the quartz-sericite schists with 
which it is interbedded. In places the rock is composed dominantly of 
cyanite, in large-bladed crystals, white to light gray or bluish-gray in color, 
and there are only minor amounts of quartz and sericite, the latter being 
sometimes practically absent; but elsewhere medium-grained saccharoidal 
quartz is predominant, with small prisms of cyanite scattered through the 
ground-mass. Rutile, occurring in small bright red grains disseminated 
indifferently through the other minerals, is the only remaining constituent 
which is ordinarily present, though tourmaline may occasionally be seen. 

The cyanite crystals range up to 7 or 8 cm. in length, and on the 
weathered surface stand out in high relief. Under the microscope (Spec. 
386) the mineral is colorless, frequently shows a slightly radiating texture, 
the cleavage is well developed, and occasionally there is a little alteration 
to sericite along the cleavage planes. Numerous irregular grains of rutile 
are present as inclusions, being usually arranged with their longer 
diameters parallel to the cleavage planes of the cyanite. The dominantly 
cyanitic variety of the schist has a noticeably high specific gravity. 

On weathered surfaces the rock is often deep red to purple in color and 
much harder than at a distance of a few inches within the interior. This 
is due to the solution of the small amount of iron originally present, and 
its transportation by capillary attraction to the surface, where it is re¬ 
deposited by evaporation, partly in the form of limonite and partly as 
hematite. 

On the southern slope of Willis Mountain, in the immediate vicinity 
of a diorite dike, the cyanite schist has been extensively altered with the 
production of new minerals, such as light brown biotite, nearly colorless 
chlorite, plagioclase feldspar, and calcite. The rock is heavily impregnated 
with pyrite, and about 40 years ago two shafts were sunk in this material 
in prospecting for copper. The rock is described in greater detail on 
page 114. 

Trent farm .—On the Trent farm, 31/2 miles southeast of Gravel Hill 
and 3 miles southwest of Hatcher, there is a dike-like ledge of cyanite 



VIRGINIA GEOLOGICAL SURVEY. 


PLATE IV. 




Fi<y. 2.—C'yanite schists outcropping on the Trent farm. 
OUTCROPS OF C'YANITE SCHIST. 






DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


29 


schist which outcrops for several hundred yards along the crest of a low 
ridge. It is 3 to 12 feet wide and in places stands 8 or 10 feet high, 
resembling a stone wall (see PL IV, fig. 2), and, indeed, it has been used 
as part of a fence to restrain cattle. This bed of schist has a strike of 
N. 10° E. and dips 30° to 40° E. 

The rock is a heavy, compact schist, pink in color, and composed 
essentially of cyanite, quartz, and sericite. The cyanite occurs in flat- 
bladed prisms ranging up to 2 or 3 cm. in length, the quartz is medium¬ 
grained with a saccharoidal texture, and the sericite is present in small, 
glistening flakes. Examined under the microscope (Spec. 393), the 
cyanite is colorless, occasionally shows polysynthetic twinning, and in 
places is partly altered to sericite. Rutile is sparingly present in small 
grains, and a little titanite was noted in some of the quartz individuals. 
Fairly well formed zircons are also present as small inclusions in the 
quartz, and there is a little limonite, partly occurring as a stain on the 
other minerals. 

The cyanite schist is interbedded with a medium-grained quartz-sericite 
schist (Spec. 394), white when fresh, and light brown to pink when stained 
with iron. Examined under the microscope, cyanite is seen to be present 
as a subordinate constituent and frequently shows multiple twinning with 
indefinite boundaries between the twins. Limonite is present as a stain 
along the contacts between the individual minerals, and also occurs in 
minute spherulites. A few inclusions of zircon are present in the quartz. 

Knotted Schists. 

GENERAL CHARACTER AND DISTRIBUTION. 

Knotted schist is the name given to a series of fine-grained rocks, com¬ 
posed essentially of quartz, sericite, chlorite, and biotite, in which there 
are numerous pseudophenocrysts of garnet, biotite, carbonate, or pyrite— 
the latter minerals being of later formation than the schistosity of the rock. 
These large crystals were formed under mass static conditions, after the 
movements which produced the cleavage of the rock had ceased, for they 
show absolutely no parallelism in their orientation. They began * to 
crystallize about favorable nuclei, and as they grew, the folia of the schist 
were gradually pushed aside, so that lenticular eyes or knots were formed, 
about which the enclosing folia are smoothly curved. The development of 
these minerals furnishes a very pretty illustration of the force exerted by 
growing crystals. 


30 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

When the knotted schists are examined in thin sections under the 
microscope, it is seen that the minerals of the ground-mass have made 
room for the crystals of later growth partly by bending and partly by 
recrystallization. The micaceous minerals of the ground-mass are imper¬ 
fectly arranged in thin layers or bands, which alternate with layers com¬ 
posed of quartz grains elongated parallel to the schistosity. Opposite the 
pseudophenocrysts, the layers of mica are pushed close together (see PI. V, 
fig. 1, and fig. 21, p. 227), while the quartz which has been removed from 
these points has recrystallized in the ends of the lenticular eyes. In other 
words, the quartz has acted very much as ice does under pressure—it has 
gone into solution where the pressure was greatest and recrystallized wdiere 
the pressure was least; and this transfer of material was undoubtedly 
brought about by the small amount of interstitual water present in the 
rock. In recrystallizing, the quartz grains have been partly arranged with 
their greater diameters oriented in directions pointing toward and away 
from the pseudophenocrysts, so that in thin sections cut parallel to the 
schistosity the quartz grains surrounding one of these larger crystals have 
a radiating texture (see PL V, fig. 2, and fig. 22, p. 228). 

The particular kind of mineral present in the lenticular knots seems 
to vary with their distance from the contact of the sedimentaries with the 
later granite intrusives; near the contact garnets are present, farther 
away biotite crystals take the place of the garnets, and at greater distances 
impure crystals of siderite form the chief constituent of the lenses. These 
facts will be considered at greater length in the detailed descriptions of 
individual occurrences and in the discussion of metamorphism (see p. 107). 

The knotted schists always have a fine-grained ground-mass, and in 
places they closely approach slates, both in fineness of texture and in per¬ 
fection of cleavage—in fact they have commonly been described as slates; 
but, since the principal mineral constituents can usually be distinguished 
with a pocket lens, it has been thought best in this report to classify them 
all as schists. 

The knotted schists constitute one of the most important members of 
the pre-Cambrian series of sedimentaries, and have a maximum thickness 
of perhaps 5,000 feet or more. They are interbedded with the other schists 
and quartzites, and are found in three principal belts. These belts are 
described below in detail. 

DETAILS OF OCCURRENCES. 

New Canton .—The best exposures of the knotted schists are furnished 
by the bluffs along the south side of James River in the vicinity of New 


VIRGINIA GEOLOGICAL SURVEY. 


PLATE V. 



Fig. 1.—Photomicrograph of biotite-bearing knotted schist; thin section cut perpen¬ 
dicular to the schistosity. With analyzer. Magnified 27 diameters. See page 
32. Specimen No. 307. 



Fj, r ■>. _Photomicrograph of garnetiferous knotted schist; thin section cut parallel 

"'to the schistosity. With analyzer. Magnified 27 diameters. See page 1(18. 
Specimen No. 178. Tellurium Mine. 

PHOTOMICROGRAPHS OF KNOTTED SCHISTS. 




DESCRIPTIVE GEOLOGY AXD PETROGRAPHY. 


31 


Canton. Here the schists are interbedded with the quartzites described 
on pages 16-18, and the whole formation is upturned so that the beds are 
now dipping almost vertical. The average strike is about X. 20° E. 

On the east, these schists extend almost to the railroad bridge over 
Phelps Creek, where they pass into the belt of hornblende schists that 
occurs along the contact between the granite and the older sedimentaries. 
This contact and the rocks in its vicinity are described in detail under 
contact metamorphism on pages 107-112. Near the bridge over James River 
the schists are interbedded with several beds of quartzite, and west of 
these the schists continue as far as the belt of Ordovician sedimentaries. 
The total breadth of the formation is nearly l 1 /*? miles and the whole series 
is apparently conformable, though it is possible that there has been some 
close folding resulting in repetition of beds. 

The river bluffs and the railroad cuts along the line of the Bucking¬ 
ham Branch of the Chesapeake and Ohio Railway, furnish an almost 
continuous exposure across the entire formation. The schists on the west 
side will be described first, as these are farthest from the contact with the 
granite, and then the variations that are encountered in passing eastward 
across the formation will be considered in detail. 

The rock exposed 1,200 yards west of Bremo bridge and about 2,000 
yards west of the contact with the granite, is a fine-grained knotted schist 
(Spec. 445), dark bluish-gray in color, containing lenticular eyes of im¬ 
pure siderite ranging up to 4 or 5 mm. in diameter. In fineness of texture 
this rock closely resembles the slates of the Ordovician formation, and but 
for the fact that it passes by gradation into the true schists, it would 
probably be preferable to classify it as slate. The rock shows a closely 
spaced fracture cleavage, which intersects the flow cleavage and bedding 
at an angle of nearly 90°. Considerable pyrrhotite is present, sometimes 
forming small lenses, and there are occasional narrow veinlets of calcite. 
The ground-mass is composed essentially of the micas—chiefly sericite, 
quartz, and a little carbonate and iron oxide. 

A specimen (444) obtained from an outcrop about 1,000 yards west 
of the bridge is typical of most of the schist found at a distance from the 
contact. The rock is fine-grained, but is slightly coarser in texture than 
the specimen last described, and the color is a much lighter shade of gray. 
It contains numerous small knots due to the presence of lenticular eyes 
of impure siderite, averaging about 1 mm. in diameter, and a little pyrite 
and pyrrhotite can be distinguished with the aid of a lens. The rock is 
cut by occasional veinlets of calcite, usually less than half an inch in thick- 


32 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

ness, which sometimes show slight symmetrical banding. In thin sections 
under the microscope the lenses of siderite are seen to be stained with 
limonite and to contain numerous inclusions of quartz and a few grains 
of iron oxide and sulphide. The ground-mass is composed essentially of 
quartz, sericite, and carbonate, with lesser amounts of pyrite, pyrrhotite, 
iron oxide, chiefly hematite, acid plagioclase feldspar, dark brown prisms 
of tourmaline, zircon, and a little chlorite. 

Schists that are identical in every way with the specimen just described 
occur within 200 yards of the bridge and are interbedded with the 
quartzites. Near the bridge, which is about 1,000 yards from the contact, 
biotite and chlorite begin to take the place of the siderite in the lenticular 
knots, and it is believed that these changes are chiefly due to the meta- 
morphic action of the granite. From this point eastward the schists show 
rapidly increasing evidence of contact metamorphism. 

A specimen (49) a from the bluffs about 25 yards west of the bridge 
is, megascopically, closely similar to the schists already described, but 
under the microscope it may be seen that many of the knots are composed 
of biotite, chlorite, and quartz instead of siderite. Lenses of siderite, 
stained with limonite, are however still present. The ground-mass con¬ 
tains sericite, quartz, chlorite, biotite, pyrite, iron oxide (hematite?), a 
few small prisms of green and brown tourmaline, zircon, and probably a 
little feldspar. 

A specimen of knotted schist (307) obtained from the bluff 400 yards 
southeast of Bremo bridge and about 800 yards from the contact, contains 
numerous rounded crystals of biotite, averaging 1 to 1.5 mm. in diameter, 
and, rarely, small pink garnets of nearly the same size. The crystals of 
biotite are dark brown to black in color and the direction of cleavage, which 
is independent of the schistosity of the rock, shows no regular orientation. 
They closely resemble the crystals of ottrelite which sometimes occur in 
similar schists. The ground-mass is slightly coarser in texture than the 
specimens previously described, and the minerals—quartz, mica, and 
magnetite—can be distinguished megascopically. 

Under the microscope, as shown in PI. V, fig. 1, the crystals of biotite 
are seen to have an irregular, ragged outline and a micropoikilitic texture 
due to the numerous inclusions of quartz. In places these inclusions are 
so plentiful that they give to the mica an appearance resembling lace-like 
network. The biotite is dark brown in color and strongly pleochroic. The 
ground-mass is composed essentially of quartz and sericite with a little 


^Specimen collected by Dr. T. P. Maynard. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 33 

chlorite, biotite, less magnetite, and, rarely, plagioclase feldspar. The 
quartz occurs in elongated grains, interleaved with tine shreds of sericite, 
all being perfectly oriented parallel to the schistosity. The small grains 
of magnetite show a similar elongation parallel to the schistosity, and the 
slide also contains clouds of uniformly distributed, dust-like inclusions, 
probably black iron ores, though they are too small to make identification 
positive. The shreds of sericite, over large areas, extinguish simul¬ 
taneously except where they curve around the large biotite crystals, and 
there the change is gradual. This gives the thin section a brilliant appear¬ 
ance between the crossed nicols. Where the flakes of sericite curve around 
the biotite crystals they are pushed close together, and the interstitial 
quartz, which has been largely removed from these points, is concentrated 
immediately in front and behind the biotite, in grains that are somewhat 
larger than those of the ground-mass. 

In passing eastward toward the contact, the crystals of biotite present 
in the lenticular knots gradually give way to garnets, and the ground-mass 
becomes a little coarser. At a distance of about 600 yards southeast of the 
bridge the garnets are numerous and well developed, while the biotite 
crystals are absent or only sparingly present. Within less than 100 yards 
from this point the rocks are close-textured, less easily cleavable, and con¬ 
tain much hornblende (see p. 109). A specimen in which the garnets 
greatly predominate over the biotite crystals (319-A) was obtained from 
the Johnson mine near New Canton, and is described in detail on pages 
254-255. 

Rogers described the schists in the vicinity of Bremo under the name of 
bird’s-eye maple slate. His statement is as follows: 

“After leaving the gneiss and hornblende slate a little below Bremo, 
we come upon heavy vertical beds of a Micaceous slate, in which are multi¬ 
tudes of half-developed garnets, and sometimes crystals of cubical pyrites 
—giving to the surface of the rock the appearance of numerous knots, 
around which the fibres of the stone are beautifully curved, so as closely 
to resemble the shading of the bird’s-eye maple.”® 

The belt of knotted schists, that has just been described, extends from 
the river in a northeasterly direction for a distance of over 6 miles. At 
the Snead mine, a mile north of Fork Union, a knotted schist is exposed 
which contains pseudophenocrysts of both garnet and biotite. The belt 
extends as far south as Willis Mountain and possibly much farther, but 
good exposures are seldom found after leaving the river. The belt of 
knotted schists passes just west of Gravel Hill, and crosses the road about 


aRogers, W. B., Geology of the Virginias, 1884, p. 78. 



34 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN'. 


iy 2 miles south of Dillwyn. In this southern portion of the area, the 
knots in the schist do not seem to be as well developed as farther north, 
but this may be more apparent than real, for all of the rock examined was 
partly decomposed. 

Strathmore .—On the west side of Bremo Creek, about 1,000 yards west 
of Strathmore, there is an outcrop of knotted schist containing well- 
developed lenticular eyes of siderite. The rock is more schistose than 
the similar schists a mile west of Bremo bridge, but it is otherwise the 
same. It outcrops at several points to the northeast and apparently extends 
for a distance of 5 miles or more in that direction, but on the south side 
of Slate River it was not found. This belt of knotted schists, while 
separated from the one that was first described by the intervening Ordovi¬ 
cian formation, undoubtedly belongs to the same series and owes its 
present position to folding and faulting. 

The Tellunum schists .—The third belt of knotted schists outcrops in 
the road at Shannon Hill and may be traced in a southwest direction 
nearly to Big Byrd Creek. It is best exposed in the underground work¬ 
ings at the Bowles, Tellurium, and Scotia mines. A representative speci¬ 
men (178) from the Tellurium mine is described on pages 168-169, and a 
photomicrograph is shown in PI. Y, fig. 2. 

Stage Junction .—A bed of micaceous schist, about 300 yards wide, is 
exposed near Stage Junction. It has a strike of 1ST. 20° E., dipping nearly 
vertical, and was traced for over l 1 /? miles. No fresh specimens could 
be obtained, but the weathered material indicates that the rock is similar 
to the knotted schists found elsewhere in the area. 

Hornblende Schists. 

GENERAL CHARACTER AND DISTRIBUTION. 

Hornblende schists, that are unquestionably sedimentary in origin, 
occur at a number of places in the pre-Cambrian area, but the origin of 
many of the hornblende schists is doubtful, and most of them are probably 
derived from igneous rocks. Because of the general character and struc¬ 
tural relations of these rocks, as well as their distribution relative to the 
later granites, it is believed that the formation of hornblende schists from 
sedimentary rocks was due chiefly to contact metamorphism, rather than 
to regional dynamic metamorphism. Hornblende schists are commonly 
present along the contact between the igneous and sedimentary rocks; 
and the few outcrops that were found at a distance from known 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


35 


occurrences of granite, may be explained by lack of exposures, though in 
some localities it is possible that erosion has not yet progressed far enough 
to expose the underlying granite. 

As it is seldom possible to distinguish between the hornblende schists 
that are sedimentary in origin and those that are igneous in origin, and 
as the majority of these rocks belong to the latter class, most of the 
occurrences will be described under igneous rocks. 

DETAILS OF OCCURRENCES. 

New Canton .—One of the best exposures of hornblende schist is fur¬ 
nished by the bluffs along Phelps Creek in the vicinity of New Canton. 
These schists occur along the contact between the sedimentary schists and 
quartzites on the west, and the granites and their accompanying differ¬ 
entiates on the east. Since this is the best exposed section crossing the 
contact, and since the schists that are sedimentary in origin grade, without 
noticeable change, into the hornblende schists that represent a basic border 
facies of the granite, a detailed description of all the rocks in the imme¬ 
diate vicinity of the contact will be given under the discussion of contact 
metamorphism (see pp. 109-112), and nothing further need be said here 
concerning them. These same hornblende schists are well exposed at the 
Johnson mine and are described on pages 248-250 and 255-256. 

Big Byrcl Creek— At the horseshoe bend in Big Byrd Creek, three- 
quarters of a mile east of Stage Junction, there is an outcrop of fine¬ 
grained hornblende schist, which is believed to be sedimentary in origin. 
The strike of the formation at this point is N. 35° E. and the dip is 40° 
S. E. The schist has a well-developed slaty cleavage, which is so marked 
that it led the owner of the property to prospect the outcrop in the hopes 
of developing good roofing slate. A garnetiferous quartz-mica schist 
occurs on the west side of the hornblende schist, and a short distance to 
the east there are outcrops of quartz-sericite schist. A large dike of 
diabase cuts the schists about 200 yards from the creek, but has in no way 
affected the rocks with which it is in contact. 

Megascopically the rock is dark gray to green in color, with a fine¬ 
grained, even-granular texture, and in places the cleavage planes show 
lens-shaped spots or blotches, 0.5 cm. in length, which are composed of 
biotite and chlorite. Small needles of black hornblende and white 
granular quartz are the principal constituents distinguishable by the naked 
eye, but some of the rock contains considerable evenly distributed biotite. 
Occasionally the schist is banded in light- and dark-colored layers parallel 
to the schistosity; the dark-colored layers being due to the presence of 
much hornblende and biotite, and the light ones to an excess of quartz. A 
little pyrite may also be identified in places. 


36 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

» 

In thin section (Spec. 51) under the microscope the rock is seen to be 
composed of dark green hornblende, quartz, feldspar, magnetite, biotite, and 
chlorite. The hornblende occurs in narrow prismatic crystals, ranging up 
to 2 mm. in length, which show good cleavage and strong absorption, the 
colors being various shades of brown, blue, and green. The quartz and 
feldspar are present in small clear grains, filling the interstices between the 
hornblende, and they occasionally contain small included needles of horn¬ 
blende. The quartz and feldspar have the same index of refraction and 
are distinguishable with difficulty, except where the latter mineral shows 
evidence of cleavage. The magnetite occurs in clusters or aggregates of 
small irregular grains. The biotite is greenish-brown in color and shows 
partial alteration to chlorite. 

Lantana .—The contact between the igneous and sedimentary rocks 
crosses the road about half a mile southeast of Lantana, and it is marked 
by a belt of hornblende schists that are similar to those occurring near 
New Canton. Exposures of fresh rock are rare in this vicinity, but along 
the branch, a mile northeast of Lantana, there are several outcrops of 
hornblende schist. 

A partly decomposed rock, outcropping on the left bank, is medium 
coarse-grained and dark green in color. The mineral constituents recog¬ 
nizable megascopieally are dark green hornblende, quartz, probably feld¬ 
spar, and a little garnet, and chlorite. A prismatic mineral (probably 
tremolite), which is light green to brown in color, is also present. 

A specimen (90) obtained from the opposite side of the branch is finer 
grained and much fresher. It is an even-granular, dark greenish-gray 
schist, in which amphibole, quartz, pyrite, and magnetite are the principal 
constituents. Part of the amphibole is green in color, but much of it is 
light gray to nearly colorless, and is doubtless tremolite. In thin sections 
under the microscope, the amphiboles are all colorless in natural light, and 
between the crossed nicols most of them show rather high interference 
colors. Twinning is sometimes shown. There is also a little acid 
plagioclase present, which is usually unstriated and therefore difficult to 
distinguish from the quartz. 

Gneisses. 

GENERAL CHARACTER AND DISTRIBUTION. 

Gneisses, believed to be sedimentary in origin, are found only in one 
portion of the area of pre-Cambrian rocks, namely, along the eastern 
border, north of James River, in the vicinity of Lantana. These gneisses 
are best exposed along Big Byrd Creek, between Bowles’ bridge, 1 y 2 miles 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


37 


northeast of Stage Junction, and the contact of the sedimentaries with the 
granites, nearly two miles below. Away from the creek there are few 
outcrops; but float is present in many places, being especially abundant 
near the branch l 1 /^ miles northeast of Lantana, and the underground 
workings of the Young American mine furnish excellent exposures of 
fresh material. All of these gneisses are confined to the area of meta¬ 
morphosed sedimentaries lying on the southeast side of an imaginary line, 
which extends from a point on Big Byrd Creek, a few yards above Bowles’ 
bridge, in a northeast direction through Pryors Crossroads. No knotted 
schists are found on the southeast side of this line. It appears certain 
that the areal distribution of the sedimentary gneisses was once much 
greater than at present, and they probably extended for a considerable 
distance toward the northeast and the southeast; but the greater part of 
these beds has long since been removed by erosion. 

Two principal varieties of gneiss were recognized—one light in color 
and composed for the most part of quartz, feldspar, and sericite; the other 
dark-colored because of the presence of more or less biotite and dark green 
hornblende. Both usually show well-developed banding. These two 
varieties occur interbedded with one another, and with beds of sericite 
quartzite, ferruginous quartzite, and quartz-sericite schists. The dark- 
colored gneiss is confined to the northwestern side of the belt and is the 
dominant rock exposed in the openings at the Young American mine, but 
its areal distribution is not so extensive as that of the lighter variety. 

GENESIS. 

The manner in which these gneisses are interbedded with one another 
and with the quartzites, leaves no doubt as to their sedimentary origin. 
4naylses of both the dark- and light-colored gneisses, made from samples 
taken 100 feet below the surface at the Young American mine, are given 
on page 124. The analyses show a striking resemblance in chemical com¬ 
position between these metamorphosed sedimentaries and igneous rocks of 
the quartz-diorite family. It is therefore probable that the sediments were 
derived from a land area composed chiefly of such rocks, and that they 
were laid down in comparatively shallow waters close to the shore. The 
conditions under which such material was derived did not permit mature 
decomposition; the land area was probably poorly covered by vegetation, 
rock disintegration was rapid, and the material formed was quickly re¬ 
moved and redeposited without appreciable sorting. The sediments laid 
down in this manner formed beds of arkosic sandstones and grits; and 
the present character of the rocks is due to dynamic regional meta- 
morphism, aided by the intrusion of the granitic rocks that partly surround 
and probably underlie these altered sediments at no great depth. 


38 


GEOLOGY OF THE GOLD BELT IX THE JAMES FIVER BASIN. 


DETAILS OF OCCURRENCES. 

Young American mine .—The freshest exposures of both the light and 
the dark varieties of gneiss were found in the lower workings of the Young 
American mine; and detailed megascopic and microscopic descriptions 
of these rocks, together with chemical analyses, are given under the 
description of this property (see pages 122-139). The difficulty of obtain¬ 
ing fresh material—for microscopic study and chemical analysis—may be 
appreciated when it is stated that, in the Young American mine, some 
of the rock is badly decomposed to a depth of nearly 100 feet below the 
surface. 

Bowles’ bridge .—On the road between Stage Junction and Pryors 
Crossroads, near the bridge over Big Byrd Creek, there are well-exposed 
outcrops of light gray gneiss. The rock (Specs. 39 and 40) is fine-grained, 
even-textured, and slightly banded; both in the hand specimen, and in 
thin section under the microscope, it closely resembles a fine-grained 
granite-gneiss. It is composed essentially of quartz, orthoclase and acid 
plagioclase feldspars, and sericite. Much calcite, probably secondary in 
origin, can be distinguished under the microscope; biotite is present in 
small dark green flakes, partly altered to chlorite; and small amounts 
of pyrite, magnetite, and zircon constitute the minor accessories. Some 
of the quartz grains show undulatory extinction, but for the most part 
there is little evidence of optical distortion or granulation. The sericite 
occurs in fairly large flakes, containing numerous inclusions of quartz, and 
it is partly of later origin than the schistosity. 

x\bout 400 yards below the bridge there is an outcrop of dark gray 
gneiss (Spec. 35), which is apparently identical in mineral composition 
as well as in texture with much of the rock exposed in the Young American 
mine. It is fine-grained, closely banded in layers of light and dark 
minerals, and composed for the most part of quartz, feldspar, biotite, 
chlorite, Sericite, and occasional garnets. Elsewhere in the same vicinity 
the rock contains much dark green hornblende. 

Bertha and Edith mine .—On Big Byrd Creek, about 1,000 yards south 
of Bowles’ bridge, there is an exposure of light gray gneiss (Spec. 32) 
similar in appearance to that at the bridge, except that it is slightly coarser 
grained. Much of the sericite occurs in large flakes in which the cleavage 
is not parallel to the schistosity, showing that it is of later formation than 
the movements which metamorphosed the sediments. The minerals 
present, in the order of their relative abundance, are quartz, feldspar, 
chiefly acid plagioclase, sericite, biotite, chlorite, magnetite, pyrite partly 
altered to limonite, zircon, and titanite. Calcite was not identified. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


39 


On Big Byrd Creek, a mile south of Bowles’ bridge, the gneiss (Spec-. 
30) is a light gray, fine-grained rock, differing but little from the speci¬ 
mens previously described. It contains less sericite, and under the micro¬ 
scope considerable epidote or zoisite can be detected. 

Where the road entering the property crosses Great Camp Branch, 
there is an outcrop of the light gray gneiss, which is within about 300 
yards of the contact of the sedimentaries with the granite. The rock 
(Spec. 48) is composed of quartz, feldspar, and sericite, with lesser 
amounts of biotite, partly altered to chlorite, garnet, zircon, and 
magnetite. 

Belzoro mine .—Near the branch half a mile north of Lantana, there 
are numerous pieces of the light gray gneiss lying loose on the surface, 
but there are no outcrops of rock in place. The same material is plentiful 
in the vicinity of the other branch, nearly a mile to the northeast. This 
gneiss (Spec. 85) is slightly banded, and, except for the sericite, is fine¬ 
grained. Some of the areas of sericite are a centimeter in diameter, and 
as the orientation of the cleavage is independent of the schistosity of the 
rock they must be of later formation. Even in the hand specimen the 
flakes of sericite are seen to be full of included quartz grains. Under 
the microscope the rock is seen to be composed chiefly of quartz, sericite, 
feldspar, with lesser amounts of biotite, partly altered to chlorite, epidote, 
garnet, magnetite, zircon, and rutile needles. Some of the feldspars show 
partial alteration to sericite, and this is probably the chief source of the 
mica. In places the sericite shows intergrowths with biotite. Zircon and 
rutile needles are very plentiful as inclusions in some of the quartz. 

ORDOVICIAN. 

General Statement. 

The Ordovician rocks are for the most part confined to a long narrow 
belt, which extends in a northeasterly direction from a point near Alpha, a 
station on the Buckingham Branch of the Chesapeake and Ohio Railway, 
to Carysbrook, a station on the Virginia Air Line Railway. A small 
elongated area of the same formation, located along the upper portion of 
Long Island Creek, between Palmyra and Wilmington, is in approximate 
alignment with the larger belt; and it seems most likely that the two areas 
were formerly continuous, and that they have been separated by the erosion 
of Rivanna River, which has removed the overlying sedimentary rocks, 
exposing the granite beneath. 

Another small area, which parallels the main belt for a short distance, 
has been prospected for slate at a point about 2 miles north of Fork 


40 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

Union Station. It was undoubtedly connected at one time with the main 
area, and has become separated through folding and erosion. 

The principal belt has a maximum width near James River of over a 
mile, but it probably averages less than half a mile; the total length, 
including the detached area on the northeast side of Rivanna River, is 
about 22 miles. 

The Ordovician series, where complete, consists of a thin bed of con¬ 
glomerate, overlain by a few feet of impure quartzite, and then followed 
by several hundred feet of slate. In places the conglomerate is composed 
of mashed pebbles of pre-Cambrian schist, and when these are small, the 
fragmental character of the rock is distinguishable with difficulty. At one 
point a layer of tuffaceous material, a few feet thick, occurs interbedded 
with the slates. 

The discovery of crinoids in slate from the Arvonia quarries was 
announced in 1892, and from a study of these fossils Dr. Walcott reached 
the conclusion that they belonged to the Trenton-Lorraine or upper por¬ 
tion of the Ordovician fauna.® Later brachiopods and trilobites were 
found, and, according to Dr. R. S. Bassler, the twelve species which have 
been identified “make up an assemblage of forms which seems to be of 
middle Cincinnatian age.” b 

Conglomerate. 

GENERAL CHARACTER AND DISTRIBUTION. 

The conglomerate occurs only at the base of the Ordovician rocks, 
where it rests upon the eroded surface of the metamorphosed, pre- 
Cambrian sediments and in places upon the granite. On the south side 
of James River the conglomerate is found along the southeastern boundary 
of the slate area, but has not been observed on the northwest boundary. 
It is not exposed in the section furnished by the bluffs along the river, 
probably because of minor faulting, which is very marked in the vicinity 
of the place where the conglomerate would be expected to appear. It out¬ 
crops, however, within about half a mile of the bluffs and can be traced 
southward for a distance of several miles. On the north side of the river 
the conglomerate was observed only on the west side of the slate, occurring 
on the road between Palmyra and Wilmington, about a quarter of a mile 
west of Long Island Creek, and in the railroad cut half a mile south of 
Carysbrook. 

aDarton, N. H.. Fossils in the “Archaean” Rocks of Central Piedmont, Virginia, 
Amer. Jour. Sci., 1892, vol. xliv, pp. 50-52. 

& Watson, Thomas L., and Powell, S. L., Fossil Evidence of the Age of the Vir¬ 
ginia Piedmont Slates, Amer. Jour Sci., 1911, vol. xxi, pp. 33-44. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


41 


The lack of suitable exposures makes it impossible in most places to 
determine the thickness of the conglomerate. Outcrops in the vicinity 
of Penlan indicate a possible thickness of perhaps 100 feet, but as the dip 
of the strata could not be determined at this point, the measurement means 
little. In the railroad cut south of Carysbrook the conglomerate is only 
a few inches thick and in places entirely disappears. 

The composition of the conglomerate varies greatly in different por¬ 
tions of the area; in places it consists almost entirely of flattened pebbles 
of schist, but pebbles of vein quartz and of quartzite are usually present, 
and sometimes there is much magnetite, graphite, and other material. Xo 
granite or feldspar pebbles were found. The rock is usually schistose 
and, where the quartz pebbles are scarce, is easily mistaken for a pre- 
Cambrian schist. The pebbles of vein quartz show no pressure effects, 
those of quartzite are usually more or less distorted, and all the softer 
material is pressed out flat. 

DETAILS OF OCCURRENCES. 

Penlan .—There are prominent outcrops of conglomerate along the 
county road about three-quarters of a mile southeast of Penlan. The rock 
contains well-rounded pebbles of quartz and also of quartzite, ranging 
up to 2 or 3 inches in diameter; but for the most part it consists of a 
fine-grained schistose ground-mass, which has been derived from pebbles 
of the neighboring pre-Cambrian schist. In places it is possible to distin¬ 
guish flattened and almost obliterated fragments of quartz-sericite schist 
and of the slate-colored, knotted schist. 

When the schistose ground-mass is examined under the microscope (Spec. 
462), clear rounded grains of quartz, ranging up to 1.5 mm. in diameter, 
can be distinguished in a ground-mass consisting chiefly of sericite, 
chlorite, quartz, and black oxide of iron. The larger quartz grains seem 
to have grown slightly at the expense of the surrounding material, for 
they have irregular outlines, with little spurs running out into the ground- 
mass, and frequently contain numerous inclusions along their border 
portions. Gas and fluid inclusions are plentiful in some of the quartz. 
Glistening plates of hematite, and a few grains of magnetite make up the 
remaining accessories. 

Outcrops of conglomerate similar to that just described are exposed 
along the road running northeast and southwest, about half a mile south¬ 
east of Arvonia, and at numerous other points along the same line of strike. 

Carysbrook .—In the railroad cut half a mile south of Carysbrook, the 
Ordovician sediments can be seen resting directly on the eroded surface 
of the granite (see PI. VI, fig. 1). There is in most places a thin line 
of pebbles in contact with the granite, but sometimes even this is absent. 


42 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


A bed of impure quartzite, about 10 feet thick, rests on top of the con¬ 
glomerate, or where this is absent on the granite, and above the quartzite 
occurs the slate. The pebbles are chiefly of quartz, but fragments of slaty 
rock are present, and also much graphitic material. The latter is soft, 
disintegrating rapidly, and leaving cavities in the weathered surface. The 
pebbles are cemented together by fine-grained, impure quartzite. 

Long Island Creel \—There is an outcrop of highly ferruginous con¬ 
glomerate on the road between Palmyra and Wilmington, about a quarter 
of a mile west of Long Island Creek. The rock is dark gray, very schistose, 
and consists of flat, lens-shaped pebbles of quartzite, in a chloritic ground- 
mass, containing a large amount of fine-grained magnetite. Under the 
microscope (Spec. 486) the magnetite apparently constitutes 40 or 50 
per cent, of the mass, the remainder being made up of quartz, chlorite, 
and sericite, in the order named. The smaller grains of magnetite are 
commonly idiomorphic, but the larger grains, ranging up to 1 or 2 mm. 
in diameter, are irregular in shape. 

Quartzite. 

The best exposure of Ordovician quartzite is the one which may be 
seen in the railroad cut, half a mile south of Carysbrook. The rock is 
only about 10 feet thick and varies somewhat in texture. It is nearly 
even-granular, slightly schistose, and of a light bluish-gray color. In 
thin sections (Specs. 509 and 510) under the microscope, the quartz 
grains show optical distortion and some granulation, and they have partly 
recrystallized so as to fill the interstitial spaces. They contain liquid- 
and gas-filled cavities, and small black inclusions (iron oxide?) arranged 
in lines which pass across the quartz grains. In places these lines are 
very numerous, suggesting fractures that have been recemented. Sericite 
is the principal impurity, and there are occasional short prisms of brown 
tourmaline. Zircon and small rutile needles occur as inclusions in some 
of the quartz. 

A bed of quartzite also outcrops in the road about half a mile southeast 
of Penlan, but its thickness could not be determined. It is separated from 
the conglomerate described on page 41 by a bed of schist which is probably 
formed chiefly from fragments of the pre-Cambrian schist. 

Schist. 

A light gray schist, closely resembling some of the pre-Cambrian 
schists, outcrops in the road about half a mile south of Arvonia, and not 


•VIRGINIA GEOLOGICAL SURVEY. 


PLATE VI. 



Fig. 1.—Ordovician sediments resting on eroded surface of massive granite near 
Carysbrook. A thin line of conglomerate runs between the hat and hammer. 



Fig. 2.—Looking north along summit of Willis Mountain. Piedmont peneplain 
in background. 

ORDOVICIAN SEDIMENTS ON GRANITE, AND WILLIS MOUNTAIN. 








VIRGINIA GEOLOGICAL SURVEY. 


ELATE VII. 



Fig. 1.—Bed of tuff in Ordovician slates. Bluffs on the south side of James River. 



Fig. 2.—Fault in Ordovician slates. Bluffs on south side of James River. 
BED OF TUFF AND FAULT IN ORDOVICIAN SLATES. 






DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


43 


far from the conglomerate. The rock is clearly fragmental in origin and 
exhibits two directions of cleavage—one due to bedding, and the other to 
pressure—which intersect at an angle of about 40°. It is composed essen¬ 
tially of quartz, sericite, and chlorite, and contains occasional lenticular 
eyes of quartz 1 to 2 mm. in diameter. Under the microscope (Spec. 
Xo. l) a the lenticular eyes are seen to be partly quartzite, and partly clear 
grains of quartz, some of which show evidence of enlarged borders. Liquid 
and gas inclusions, and a little zircon and titanite may also be identified. 
This rock is similar to the schist which occurs between the conglomerate 
and the quartzite about half a mile southeast of Penlan. 

Tuff. 

A bed of tuffaceous material is exposed in the bluff near the eastern 
border of the slate area and a mile west of Bremo bridge. It is inter- 
bedded with black graphitic slates, which in places contain much pyrite. 
A photograph of the bed is shown in PI. VII, fig. 1. Close to the hammer 
a nearly vertical fault can be seen, on the left of which the beds stand 
almost vertical, while on the right they are much contorted but nearly 
horizontal. The tuff is the light-colored material near the hammer. Xo 
other beds of tuff were identified in the area. 

The tuff (Spec. 494) is a fine-grained, gray, slate-colored rock, dis¬ 
tinctly fragmental to the naked eye, and very schistose, so that the frag¬ 
ments are drawn out in long streaks. Fine flakes of sericite, small grains 
of quartz, and a little pyrite are the only minerals distinguishable mega- 
scopically. Under the microscope it is seen to consist chiefly of fine-grained 
quartz, sericite, with numerous larger grains of quartz, averaging less than 
0.5 mm. in diameter, and occasional small phenocrysts of feldspar (ortho- 
c-lase and acid plagioclase). Calcite is plentifully distributed through 
the section, and pyrite partly altered to limonite, occurs in small grains. 
Very fine, dust-like inclusions (graphite or iron oxide) are abundant 
throughout the slide. 

Slate. 

GENERAL CPIARACTER AND DISTRIBUTION. 

Slate is the dominant rock of the Ordovician series of sedimentaries, 
and the beds probably have a thickness of more than 1,000 feet, but 
because of the complicated folding and faulting only a rough estimate can 
be made. The areal distribution of the slate is coincident with that of 
the formation as a whole, for the thickness of the other members is in¬ 
significant in comparison with that of the slate. 

^Microscopic thin section made from specimen collected by Dr. T. P. Maynard. 





44 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

The slate has a finely granular, crystalline texture, it is dark gray to 
black in color, and usually has a rather rough though very lustrous cleav¬ 
age surface. It is graphitic and usually slightly magnetitic, contains a 
little pyrite, does not effervesce in cold dilute hydrochloric acid, and is very 
sonorous. The degree of cleavability varies greatly in different parts of 
the area, but is usually high, so that the slate can be split readily into 
slabs of any desired thickness. 

In the vicinity of Arvonia the slate has been extensively quarried for 
roofing and other purposes, and at a number of places along the strike of 
the formation prospecting has been carried on with very encouraging 
results. Because of its highly crystalline character, the slate has great 
strength and durability, and some of it, used in roofing buildings over a 
century ago, shows no discoloration from its long exposure. All of the 
slate in this area is not, however, available for commercial purposes, as 
the value of some of it is destroyed by close folding and faulting, and in 
a few localities the cleavage is not sufficiently developed. 

DETAILS OF OCCURRENCES. 

A detailed report on the slate deposits of Virginia is now in prepara¬ 
tion, and will be published shortly as Bulletin No. X of the State 
Geological Survey; therefore the following descriptions will be brief, and 
for the most part limited to facts bearing on the structural relations of 
the slate formation. 

Arvonia .—At Arvonia there are extensive quarries, all of which are 
located on the east side of the slate belt. In these openings the bedding 
and cleavage of the slate are identical, striking X. 33° to 37° E. and 
dipping 70° to 90° southeast. There are three sets of joints, namely, 
vertical dip joints striking northwest; strike joints, running northeast 
and southwest and dipping 70° to 80° southeast; and diagonal joints some 
of which dip 30° east while others dip 55° west. Quartz veins are occa¬ 
sionally present, some of which contain calcite, and a little chlorite and 
biotite. In one of the quarries a dike of olivine diabase is exposed, which 
is 12 feet thick and traverses the slate diagonally. 

The slate is very dark gray, with a faint greenish hue; it shows a 
distinctly granular crystalline texture to the naked eye; and has a highly 
lustrous cleavage surface, which is commonly rough or slightly wrinkled 
because of the presence of small flakes of biotite and of minute grains of 
the iron ores. According to Dale® the mineral constituents, in the order 

flDale, T. N., Slate Deposits and Slate Industry of the United States, Bull. U. S. 
Geol. Survey, No. 275, 1906, p. 114. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


45 


of their relative abundance, are muscovite and sericite, quartz, biotite, 
carbonate, graphite (or carbonaceous matter), pyrite, chlorite, magnetite, 
with accessory plagioclase, zircon, hematite, tourmaline, and rutile. 

The following microscopic description of the slate from the Williams 
quarries is given by Dale, and may be taken as representative of the other 
quarries in this vicinity: 

“Under the microscope it shows a matrix of minute alternating beds, 
chiefly of fine muscovite, with coarser ones, chiefly of quartz, the former 
with a brilliant aggregate polarization, the latter with a faint one. These 
beds are parallel to the cleavage. The quartz fragments measure up to 
0.085 mm. Scattered throughout both the more micaceous and the more 
quartzose beds are crystals, lenses, and particles of pyrite, numbering 
about 25 to each square millimeter and measuring up to 0.09 mm., rarely 
0.15 and 0.42, with their longer axes parallel to the cleavage. These 
probably include a little magnetite. There are also biotite scales trans¬ 
verse to the cleavage, about 22 per square millimeter, and measuring up 
to 0.12, rarely 0.2 mm. Almost, if not quite, as abundant are plates and 
rhombs of carbonate. There are occasional scales of chlorite interleaved 
with muscovite, a few grains of plagioclase feldspar 0.047 mm., rarely 
one of zircon, some tourmaline prisms 0.014 mm. long, much extremely 
fine graphitic (or carbonaceous?) material, a few particles of hematite, 
and some rutile needles. Sections parallel to the cleavage are unusually 
brilliant in polarized light, owing to the abundance of quartz, biotite, and 
carbonate.”® 

Bluffs along James River .—The slates exposed in the bluffs along the 
south side of James River show evidence of much close folding and fault¬ 
ing (see PI. VII). Near the fault shown in Pig. 2, which is located close 
to the railroad, 500 yards south of the mouth of Slate River, the slate has 
two equally developed cleavages intersecting at an angle of about 5°. One 
of these is the ordinary slaty cleavage due to pressure, and the other is 
probably slip cleavage due to minute faulting. As the two cleavage sur¬ 
faces reflect light at slightly different angles, the slate has a very striking 
appearance. About a quarter of a mile farther east a similar slate is 
exposed, in which the angle between the two cleavages is 25°, but one is 
much better developed than the other. It is possible that one cleavage is 
due to bedding. 

Some of the slates are highly graphitic, and in others pyrite is very 
plentiful, occurring in thin layers parallel to the bedding. Hematite is 
occasionally present in the form of thin plates, a fraction of a millimeter 
in diameter. 

Carysbroolc .—The slate exposed in the railroad cut half a mile south 
of Carysbrook is wholly lacking in slaty cleavage, but has a distinctly 


«Dale, T. N., Ibid., pp. 113-114. 



46 GEOLOGY OF THE GOLD BELT IN THE JAMES FIVER BASIN. 

schistose structure parallel to the strike of the formation, which causes 
the rock to break in roughly prismatic shapes. This peculiarity is probably 
clue to the location of the material at the bottom of a synclinal fold, where 
the pressure was approximately equal in all directions except along the 
axis of folding. 

The strike of the formation is about N. 25° E. and there are three 
principal sets of jointing, namely, nearly vertical strike joints running 
northeast and southwest; joints which dip about 30° southeast and are 
approximately parallel to the contact with the underlying granite; and 
transverse joints having a strike of 1ST. 60° W. and dip of 75° northeast. 
The latter are spaced 2 to 8 inches apart. 

The slate (Spec. 505) is dark gray, with little luster, and contains 
numerous flat discs of specular hematite, which are oriented in all direc¬ 
tions parallel to the axis of folding. These plates vary in diameter up to 
1 mm. and in thickness up to 0.1 mm. 

Examined microscopically the chief constituents of the ground-mass 
are, in the order of their relative abundance, sericite, quartz, chlorite, with 
accessory tourmaline, and zircon. Some of the quartz occurs in lenticular 
eyes less than 0.5 millimeter in length, which occasionally contain small 
fragments of zircon. Prisms of greenish-brown tourmaline, ranging up 
to 0.2 millimeter in .length, are fairly plentiful, and are usually oriented 
parallel to the schistosity. Some of the thin discs of hematite contain 
numerous small inclusions of quartz. 

TRIASSIC. 

The small area of sedimentary rocks shown on the map (PI. I), between 
Ca Ira and Willis Mountain, belongs to the Triassic (Xewark) system, 
and is the northern end of the Farmville area, which extends in a south¬ 
westerly direction for a distance of over 20 miles. In this northern por¬ 
tion the rocks consist of gently dipping beds of conglomerate, sandstone, 
and shale. They are deep red in color, and are in marked contrast to 
the surrounding crystalline rocks, chiefly granite and pegmatite, which 
weather to a light gray soil. Near Farmville fine, light-colored sand¬ 
stones and shales occur interbedded with several small coal seams, the 
lighter color being undoubtedly due to the reducing action of the car¬ 
bonaceous matter. 

The area as a whole is, topographically, a basin surrounded by hills 
of crystalline rocks, but lack of exposures make it difficult to work out the 
detailed geologic structure. The stratified rocks of the Triassic rest un- 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


47 


conformably on the metamorphosed pre-Cambrian sediments and the 
granites; and these underlying formations dip steeply toward the south¬ 
east. The Triassic beds are much disturbed, changing abruptly from 
northeast to southwest dips, and Bussell determined the presence of at 
least four north and south faults.® One of these faults forms the eastern 
border of the area about 2 miles north of Farmville, and there the stratified 
rocks are much broken and slickensided. In the absence of better ex¬ 
posures, it is impossible to measure the thickness of the beds, but every¬ 
thing indicates that they are of no great depth. 

The rocks of the Triassic system have not undergone the great crustal 
movements which have so intensely metamorphosed the older rocks of the 
area; indeed, for the most part, they have not been thoroughly consoli¬ 
dated. Since these rocks have not extensive areal distribution in the 
region mapped, and since they are of no economic importance, they will 
not be discussed in this report. 

ROCKS IGNEOUS IN ORIGIN. 

GENERAL CLASSIFICATION. 

The rocks of igneous origin described in this report are classified, in 
so far as possible, according to their relative age. The position of some 
of these rocks in the geological column is accurately known, that of others 
can be determined within comparatively narrow limits, and in a few 
instances there is considerable uncertainty. As in the case of the sedi¬ 
mentary rocks, the chief criterion used in distinguishing between the pre- 
Cambrian and the later rocks is that of relative schistosity, while the 
position of others is determined by their relation to sedimentaries of 
known age. Under the description of each rock type, the evidence upon 
which its age classification is based is given in detail. The principal groups 
into which the igneous rocks have been divided are: (1) Pre-Cambrian, 
(2) pre-Cambrian and Cambrian, (3) Cambrian or post-Cambrian, and 
(4) Triassic. 

PRE-CAMBRIAN. 

Greenstone Schists. 

GENERAL CHARACTER AND DISTRIBUTION. 

A large area of greenstone schists is present along the northwestern 
border of the map, given on PI. I, and extends for several miles to the 
westward. The southeast contact between these schists and the other 
pre-Cambrian rocks crosses James River about 1,000 yards west of Strath- 

flRussell, I. C., Correlation Papers. The Newark System. Bull. No. 85, U. S. 
Geol. Survey, 1892, pp. 88-89. 



48 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

more, and continues in a general southwesterly direction for an unknown 
distance; passing northeast the greenstone schists apparently pinch out 
in the vicinity of Palmyra. On Slate River, 500 yards west of Hunts 
Creek, Ordovician slates are apparently in contact with the greenstone 
schists for a short distance. 

Chloritic schists are common in the region between Wilmington and 
Kent’s Store, and occur at several other localities in the area mapped, 
but as these rocks are derived chiefly from the hornblende schists that are 
found associated with the granites, they will be described under that 
heading. 

The rocks in the large area of greenstone schists vary in texture from 
dense aphanitic varieties to those that are medium fine-grained, and in 
places porphyritic. They usually show a pronounced schistose structure 
but some of the coarser grained rocks, which have undergone less altera¬ 
tion, are more nearly massive. The color is always green, and varies in 
shade according to the relative amounts of chlorite and epidote present 
in the rock. 

The mineral constituents present in these rocks are quartz, chlorite, 
epidote, amphibole, calcite, plagioclase, magnetite, pyrite, and in 
some instances small amounts of rutile, ilmenite, and titanite. Very rarely 
a little chalcopyrite or malachite can be identified. 

Quartz and usually calcite are present in the ground-mass of the rock 
and these minerals also frequently occur as eyes and veinlets. The feld¬ 
spars, and part of the quartz and magnetite, are the chief primary minerals 
that remain unaltered. The feldspars are basic plagioclase, and frequently 
show Carlsbad as well as albite twinning. Chlorite is abundant in all of 
the rocks, occurring in fine-grained dark green scales. Epidote is most 
plentiful along fracture lines, and it also occurs in some of the veinlets. 

Small slickensided surfaces are common throughout the rock; they 
run in various directions but are usually approximately parallel to the 
schistosity. They are probably to be explained by the volumetric expan¬ 
sion which has resulted from the alteration of the rock, with the formation 
of hydrous from anhydrous silicates. 

Microscopic examination of a large number of thin sections of the 
greenstone schists, shows that they are derived from basic igneous rocks, 
but the alteration has been so extensive that in most cases it is impossible 
to determine their original character. The texture in a few localities 
suggests that part of the schists were formed from massive rocks of deep- 
seated origin, but it is not improbable that they are largely derived from 
basic lava flows. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


49 


AGE. 

The intense regional metamorphism which has affected all of the older 
rocks, and the lack of suitable exposures along the contact, make it im¬ 
possible to determine the relation of the greenstones to the other pre- 
Cambrian schists. When the surrounding portions of the Piedmont 
province have been mapped in detail some light will probably be shed on 
this question, but at present it is not even possible to make a statement 
concerning the relative age of the two formations. At the London and 
Virginia mine (see pp. 185-186) a chloritic schist is interbedded with the 
quartz-sericite schists but it is different in appearance and has probably had 
a different origin. The greenstone schists are classified as pre-Cambrian 
in age because of their extensive metamorphism under dynamic condi¬ 
tions, and because of the presence of gold-bearing quartz veins believed to 
be Cambrian in age. They resemble the Catoctin schist of the Blue Ridge 
and may be contemporaneous in age. 

DETAILS OF OCCURRENCES. 

Slate River .—The bluffs along Slate River, west of the mouth of Hunts 
Creek, furnish some of the best exposures of greenstone schist that are to 
be found in the district, and this section will be described in detail. The 
contact between the Ordovician slates and the greenstone schists crosses 
Slate River about 500 yards west of Hunts Creek, but is not exposed. On 
the south bank of the river just west of the contact there is a hold, cliff¬ 
like outcrop of the schist. 

The rock (Spec. 495) is dark green, fine-grained, even-granular, and 
not quite as schistose as in most localities. Quartz, chlorite, and a few 
small cubes of pyrite are the only minerals recognizable megascopically. 
Under the microscope the rock is seen to be composed of quartz, chlorite, 
plagiocase feldspar, calcite, talc, epidote, and a little fine-grained magnetite. 
The quartz grains are slightly larger than the other minerals, and are 
frequently arranged in irregular lines and flat lenses parallel to the 
schistosity. The feldspars are ragged in outline and show extensive alter¬ 
ation to the secondary minerals of which the rock is chiefly composed. 
The chlorite and other minerals are very fine-grained. 

A few yards farther west the rock (Spec. 448) is slightly finer grained, 
more schistose, and contains occasional lenticular eyes of fine-grained 
white quartz 3 or 4 mm. in diameter. Examined under the microscope 
the lenticular eyes are seen to consist of clear rounded, interlocking grains 
of quartz, which contain small gas- and liquid-filled cavities and numerous 


50 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


rutile needles. Basic plagioclase feldspars are present, some of which 
show fractures filled with a fine-grained ground-mass, consisting chiefly 
of chlorite. Calcite, epidote, and zoisite make up .the remaining mineral 
constituents. 

Greenstone schists, essentially similar to those just described, continue 
for several miles up the river with only a little variation here and there. 
In one place a peculiar veinlet (Spec. 449) about a quarter of an inch 
wide, was seen cutting the schist. It consists of dark green micaceous 
chlorite, with cleavage parallel to the walls, and phenocrysts of white 
feldspar, 3 to 4 mm. long, which project out from the walls of the veinlet. 
The feldspars show twinning after both the Carlsbad and the albite laws. 
Xearly a mile west of the creek, a light green rock outcrops which is nearly 
massive in texture. It is medium coarse-grained, and is composed for the 
most part of light green hornblende and feldspar. The hornblende is 
partly altered to chlorite. It is evidently an igneous rock (probably 
diorite), which has been only slightly altered. 

At the Lightfoot mine, on the southeast side of Slate River, 2 miles 
northwest of Arvonia, the country rock is the typical greenstone schist 
found everywhere in this section. It is described in detail on pages 241-242. 

Liglitfoot farm. — On the farm of P. W. Lightfoot, 1% miles 1ST. 15° E. 
of Arvonia, an 18-foot shaft has been sunk in prospecting for copper. 
Most of the rock exposed on the dump is a fine-grained greenstone schist 
containing scattered crystals of pyrite, less than 0.5 mm. in diameter, and 
much fine-grained magnetite. In places there are small segregated areas 
containing pyrite in coarse, irregular crystals associated with white quartz. 
A few pieces of rock were seen which contained partly altered phenocrysts 
of feldspar, 2 cm. in length. 

At several points in this vicinity a few small specks of malachite can 
be seen in the country rock. Pebbles of magnetite are found on the sur¬ 
face in places where they have weatherd out from the greenstone. 

Anaconda mine .—The greenstone schist at the Anaconda mine, near 
Eldridge Mill, is described on page 244. About 400 yards northeast of the 
mine several small surface openings have been made in prospecting for 
asbestos. Some chlorite schist is exposed in these pits, but most of the 
rock is a light green talc which usually contains a few scattered needles 
of amphibole, probably actinolite. In places there are large masses of 
amphibole asbestos, part of the fiber being 7 to 8 inches in length, but 
much of it is cut by joint planes spaced about 2 inches apart. Masses,, 
composed chiefly of actinolite in more or less radiating crystals, are present 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


51 


on the dump. Magnetite in small grains is scattered through both the 
chloritic and talcose schists. 

Shores .—A quarry for railroad ballast is located on the Chesapeake 
and Ohio Railway about three-quarters of a mile southeast of Shores. The 
rock exposed is dark green in color, fine-grained, and is cut by numerous 
small segregation veinlets consisting of white, fine-grained quartz, and a 
little calcite and dolomite. These veinlets do not have sharp, well-defined 
walls but pass by gradation into the schist. The minerals present in the 
rock, which can be identified megascopically, are quartz, chlorite, calcite, 
magnetite, and epidote. The greenstone schist extends westward beyond 
Shores. 

Hughes mine .—The gold veins at the Hughes mine, which is located 
on the Virginia Air Line Railway, 2 miles northeast of Fork Union station, 
occur in an area of greenstone schist. Specimens of the wall rock from 
this mine are described in detail on pages 182-183. 

Palmyra .—In the vicinity of Palmyra and northwest from the town a 
greenstone schist is exposed, and in places the chloritic schists enclose 
masses of talc and steatite which have been worked to a limited extent. It 
is reported that a little copper ore was found on the west side of Rivanna 
River opposite Palmyra, occurring in greenstone schist similar to that 
near the Lightfoot mine. 

Quartz-Feldspar Porphyries. 

A series of quartz-feldspar porphyries are exposed along Rivanna River 
about a mile south of Palmyra. These rocks vary from light to dark gray 
in color and from fine- to medium-grained; they are usually porphyritic 
to the naked eye, containing feldspar phenocrysts and eyes of blue opal¬ 
escent quartz; and they all exhibit varying degrees of scliistosity. In thin 
section under the microscope they are seen to consist essentially of quartz, 
potash and soda-lime feldspars, and certain secondary minerals such as 
sericite, calcite, chlorite, and epidote. The eyes of quartz usually show 
strain shadows, more or less fracturing, and granulation; and they fre¬ 
quently contain rutile needles and gas- and liquid-filled cavities. The 
potash feldspars include both orthoclase and microcline, and these as well 
as the acid plagioclase are extensively altered with the production of the 
secondary minerals mentioned above. There is also a little microperthite 
in some of the rock. The minor accessories comprise magnetite, ilmenite 
partly altered to leucoxene, titanite, and pyrite. 

Rocks similar to these porphyries were not found elsewhere in the area 
mapped. It is possible that they are genetically connected with the in- 


52 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

trusive granites, but no evidence in support of this supposition could be 
discovered. For the most part these porphyries are more schistose than 
the granites and therefore they are probably older. 

Rhyolites. 

GENERAL DESCRIPTION AND AGE RELATIONS. 

Rhyolites occur interbedded with schists and other rocks at several 
points near the western border of the area mapped, but they are of no 
importance as geologic formations. They are light gray, hard, dense- 
textured rocks, and all show a schistose or slaty cleavage, which becomes 
more marked in the weathered specimens. Watson and Powell noted the 
occurrence of these rocks south of James River in the Arvonia slate belt 
and described similar ones in the Quantico slate belt, where they occur 
interbedded with the slates which are Ordovician in age.® The rhyolites 
in the James River section may be contemporaneous with those in the 
Quantico belt, but the writer found no evidence to indicate that this is 
true. Because of their marked schistosity they are here described with 
the pre-Cambrian rocks, although it is possible that they are younger. 

DETAILS OF OCCURRENCES. 

Bremo Bluff .—On the south side of James River, about three-quarters 
of a mile west of Bremo bridge, there is an exposure of rhyolite, about 
20 feet thick, which is interbedded with knotted schists. The rock is light 
gray, dense-textured, and in places contains elongated spots due to gas 
cavities or to some mineral which has undergone decomposition. It has 
a slaty cleavage, which, while scarcely noticeable in the fresher specimens, 
becomes very prominent in the weathered rock. Under the microscope 
(Spec. 493) the rock is distinctly schistose and is seen to be composed of 
quartz, feldspar, biotite, chlorite, black iron oxide, partly magnetite, 
sericite, zircon, tourmaline, titanite, and small areas of glass. 

Slate Biver .—On the south side of Slate River about half a mile west 
of Hunts Creek there is a small outcrop of siliceous rock (Spec. 450), 
which is hard, close-textured, white in color, and very schistose. It is 
probably a metamorphosed rhyolite. This rock occurs in the area of green¬ 
stone schists derived from basic igneous rocks. 

Ballinger Creek .—About 1% miles east of Palmyra on the road to 
Wilmington, and 200 yards east of Ballinger Creek, there is an outcrop 

aWatson, Thomas L., and Powell, S. L., Fossil Evidence of the Age of the Vir¬ 
ginia Piedmont Slates, Amer. Jour. Sci., 1911, vol. xxxi, pp. 33-44. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


53 


of rhyolite which is closely similar to the rock found west of Bremo bridge. 
It is slightly more schistose in the hand specimen (485) and in thin 
section under the microscope it is seen to be porphyritic, containing pheno- 
crysts of quartz and acid plagioclase feldspar about 0.25 mm. in diameter. 
The quartz eyes contain gas- and liquid-filled cavities. The ground-mass 
is composed of quartz, feldspar, biotite, chlorite, and sericite. 

Palmyra .—A short distance south of the railway station at Palmyra 
there is an outcrop of schistose rhyolite, in which small eyes of quartz 
can be distinguished by the naked eye. Examined in thin section (Spec. 
14 ) a under the microscope, small eyes of quartz and phenocrysts of ortho- 
clase, 1 mm. in length, which usually show Carlsbad twinning, can be seen 
in a fine-grained ground-mass, consisting of quartz, feldspar, magnetite, 
ilmenite partly altered to leueoxene, and a little chlorite and epidote. 

PRE-CAMBRIAN AND CAMBRIAN. 

Granites, Their Associated Pegmatites and Hornblende Schists. 

INTRODUCTORY STATEMENT. 

The granites and their associated differentiates, occupying about two- 
thirds of the area mapped, are confined to the eastern portion (see PI. I). 
Similar rocks continue beyond the limits of the map and extend eastward 
for an unknown distance, for below the falls at Richmond they are covered 
by the later sediments of the Coastal Plain. 

These rocks, while for the most part closely related, belong to several 
periods of intrusion, and vary in character and mineral composition 
within comparatively short distances. In composition they range from 
true granites, in which potash feldspars are dominant over plagioclase, 
through granodiorites and quartz-diorites, to rocks that are composed 
almost exclusively of hornblende—every gradation between the two 
extremes being found. Quartz is always present, the more acid rocks con¬ 
tain muscovite, and biotite usually occurs in all except the most basic 
varieties, where it is completely replaced by hornblende. With the appear¬ 
ance of hornblende in the rocks the potash feldspars disappear. The 
dominant rock type of the area corresponds to granodiorite or quartz-diorite 
in mineral composition. Pegmatites in places accompany the more acid 
facies, and pegmatitic quartz veins carrying a little mica are also present. 

The large granite area occupying the eastern half of the map (see 
PI. II) will be divided, for convenience in mapping and description, into 

aThis thin section was made from a specimen collected by Dr. <T. S. Grasty. 


3 




54 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

4 separate divisions or belts, running in a northeast and southwest 
direction, in each of which the rocks exhibit certain peculiar characteristics. 
Passing from east to west these subdivisions are (1) the Cartersville area, 
(2) the Elk Hill complex, (3) the pegmatite belt, and (4) the Columbia 
area. In addition to these there are several smaller areas which occur 
within the boundaries of the pre-Cambrian sedimentaries, namely, the 
Gold Hill area lying between Kent’s Store and Tabscott, the Rosney area 
near the southern border of the map, and an area of unknown but limited 
extent, in which the only exposures are at the Greeley mine. Each of these 
areas is described in detail below. 

AGE. 

The granites are younger than the pre-Cambrian rocks with which they 
are in contact, but the high degree of schistosity shown by most of the 
granites is proof of their solidification prior to the cessation of the great 
crustal movements that preceded the Cambrian. Evidence that the period 
covered by the intrusion and solidification of the granites continued until 
after the close of these great movements, is furnished by the fact that the 
last of the granites to crystallize are practically massive in texture. 
Similar evidence is furnished by the lack of schistosity in many of the 
pegmatites and aplites, which are residual differentiates from the granite 
magma, and are therefore of later crystallization. 

Granites crystallize under conditions of deep burial, and therefore much 
overlying material must be removed by erosion before they are exposed. 
Hear Carysbrook, Ordovician sediments may be seen resting on the eroded 
surface of almost massive granite, and this indicates that a considerable 
time interval must have elapsed between the solidification of the youngest 
granite and the deposition of the sediments in Ordovician time. 

A consideration of the facts outlined above leads to the conclusion that 
the intrusion of the granites probably began during the pre-Cambrian 
and continued into the early Cambrian. It is not unlikely that the crustal 
movements which terminated the pre-Cambrian, and the intrusion of the 
granites, are both manifestations of the same general forces. 

Cartersville Area. 

GENERAL DESCRIPTION. 

The Cartersville area occupies the southeast corner of the map (PI. II) 
and its northwestern boundary, passing between Elk Hill and Pemberton, 
extends in a general southwesterly direction approximately parallel to and 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


55 


just west of the ridge road leading from Cartersville to Cumberland. 
There are very few rock exposures in this area except in the vicinity of 
James River. The outcrops in the bluffs along James River and the 
occasional exposures found elsewhere indicate that the dominant rock is 
a fine-grained, light gray granite-gneiss, containing much muscovite and 
usually a little biotite. Pegmatites are common but the hornblende schists 
are extremely rare. 

DETAILED DESCRIPTIONS. 

Pemberton .—On the north side of James River, three-quarters of a 
mile southeast of Pemberton, there is a large outcrop of gneissic granite. 
The strike of the schistosity is nearly north and south and the dip about 
45° east. There are two varieties of rock exposed at this point; one (Spec. 
27) is the light gray muscovite granite which forms the dominant rock 
type in the Cartersville area; and the other (Spec. 28), underlying the 
first, is a highly schistose reddish-brown rock. 

Examined megascopically, the light gray granite (Spec. 27) is fine¬ 
grained and composed of white feldspars, quartz, muscovite in flakes 
ranging up to 2 or 3 mm. in diameter, a little biotite in small black specks, 
and rarely small pink garnets. Under the microscope orthoclase feldspar 
is seen to be dominant over the soda-lime feldspar (probably oligoclase), 
and no microcline seems to be present; the muscovite is apparently 
primary; and the biotite is dark brown in color, and strongly pleochroic. 
Fine hair-like needles of rutile are very plentiful, occurring in feldspar, 
quartz, and muscovite, but they seem to be most abundant in the feldspars. 

The dark-colored gneiss (Spec. 28), which underlies the rock described 
above, contains occasional lenticular eyes of feldspar and quartz. The 
rock has a peculiar reddish-brown (almost purple) color due to the 
presence of much fine-grained, brown biotite. In thin section under the 
microscope the soda-lime feldspars (probably oligoclase) are seen to be 
dominant, and there is only a little orthoclase and less microcline present. 
Some of the feldspars show zonal extinction. The biotite occurs in small 
light brown flakes and there is also some muscovite. Grains of ilmenite 
partly altered to leucoxene are common, and hair-like needles of rutile, 
sometimes curved, are occasionally present, being more numerous in the 
potash feldspars. A little pyrite and a few small grains of titanite make 
up the remaining accessory minerals. 

A mile northwest of Pemberton, the granite exposed is nearly white 
in color and almost free of biotite. The minerals recognizable in the 
hand specimen (25) are white feldspar, quartz, and muscovite, a very 


56 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

little biotite, and occasionally small pink garnets. Under the microscope 
the rock is seen to consist of irregular individuals of feldspar, quartz, and 
muscovite, ranging up to 1 mm. or over in diameter, which are surrounded 
by and grade into a finer ground-mass, composed largely of quartz and 
feldspar, and frequently granophyric in texture. Named in the order of 
their relative abundance, the mineral constituents are potash feldspar 
(chiefly microcline), quartz, soda-lime feldspar (probably oligoclase), mus¬ 
covite, and a little biotite. The albite twinning in the plagioclase is very 
fine and sometimes absent. Around their border portions the feldspars 
frequently show graphic intergrowths with quartz. The muscovite is 
partly secondary after feldspar but most of it is probably primary. Only 
a little biotite is present, occurring in small dark brown flakes which are 
partly altered to chlorite. The quartz shows strain shadows and contains 
numerous fluid-filled cavities, some of which have moving bubbles. 

Cartersville .—Fresh rock is exposed at a number of places in the 
vicinity of Muddy Creek and along the road a mile south of Cartersville. 
Most of it is the light gray muscovite granite, similar to Spec. 27, described 
above. In the road 200 yards southeast of Muddy Creek there is an out¬ 
crop of porphyritic granite. The rock (Spec. 473) contains numerous 
phenocrysts of white, unstriated feldspar ranging up to 1 cm. in diameter, 
and in places these feldspars constitute the greater part of the rock mass. 
They are surrounded by a fine-grained ground-mass of feldspar, quartz, 
biotite, and muscovite. A similar rock occurs on the opposite side of the 
river, about halfway between Pemberton and Stokes, where the feldspar 
phenocrysts range up to 5 or 6 cm. in diameter and are strung out in lines 
parallel to the schistosity. In some of the rock the large feldspars are so 
numerous that it resembles a pegmatite rather than a granite porphyry. 
The dominant rock in this vicinity, as elsewhere in the Cartersville area, 
is the light gray, muscovite granite. In places it contains pink garnets 
0.5 cm. in diameter. At several points the dominant rock is cut by dikes 
of later granite, 2 or 3 feet in thickness. This later granite is fine¬ 
grained, less schistose, and contains more biotite and less muscovite. 

Stokes .—One of the few places in the Cartesville area where horn¬ 
blende rocks occur is located above three-quarters of a mile west of Stokes. 
At this point there is a small outcrop of fine-grained, even-granular schist, 
showing slightly gneissic banding, and composed essentially of quartz, 
feldspar, black hornblende, and epidote. The surrounding rock is chiefly 
a muscovite granite with occasional outcrops of pegmatite. 





VIRGINIA GEOLOGICAL SURVEY. 


PLATE VIII. 



Fig. 1.—Flow structure in banded gneiss intruded between layers of hornblende 
schist. 



Fig. 2.—Photomicrograph of 
mine. With analyzer. 
No. 217. 


plagioclase feldspar in vein quartz from the Waller 
Magnified 27 diameters. See page 149. Specimen 


FLOW STRUCTURE AND PLAGIOCLASE FELDSPAR. 





DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


57 


Elk Hill Complex. 

GENERAL DESCRIPTION. 

The Elk Hill complex is made up of three principal rock types—biotite 
granite, hornblende schist, and pegmatite—which occur interleaved in 
layers, of varying thickness and in places are much contorted. The horn- 
blendic rock appears to have been formed first and the granite intruded 
into it later, while the pegmatite frequently cuts both of the other rocks. 
The complex is from one to U/o miles wide where it crosses James Eiver 
at Elk Hill, and the best exposures are found in the bluffs three-quarters 
of a mile below Elk Hill. There are exposures along the road 1% to 2 
miles east of Flanagan Mills, and also in the road just southeast of Fife, 
but at neither of these localities is it possible to obtain fresh material. 

DETAILED DESCRIPTIONS. 

Excellent outcrops of fresh rock occur along the bluffs, three-quarters 
of a mile southeast of Elk Hill, where much blasting was done to make 
room for the old James River canal. In the photograph shown in PI. VIII, 
fig. 1, the straight dark bands are hornblende schist, while the light- 
colored layers consist of biotite granite and pegmatite. The contortions 
seen in the layer or dike of granite, which occupies the center of the photo¬ 
graph, probably represent flow structure, for if they were formed by crustal 
movements occurring after the complete solidification of the rock the layers 
of hornblende schist would likewise have been affected. The light-colored 
bands in the granite are pegmatitic in character. Elsewhere in the imme¬ 
diate vicinity the granite may be seen cutting across the hornblendic rock 
while the veinlets of pegmatite sometimes stop short at the contact and 
sometimes cut across both rocks. 

The hornblende schist (Spec. 22) is dark gray to nearly black in color, 
and is composed of black hornblende, in crystals ranging up to 2 or 3 
mm. in length, white feldspar, and a little black biotite. Small grains of 
pink garnet can be identified in places. The rock is cut by narrow, ir¬ 
regular veinlets of white feldspar and quartz, and contains lenticular eyes 
of feldspar 2 cm. and less in diameter. Occasionally a little fine multiple 
twinning can be distinguished on these feldspars. Under the microscope 
the hornblende shows perfect cleavage and is pleochroic in shades of 
light green, greenish-blue, and brown. The feldspars are plagioclase 
(probably oligoclase) and sometimes show zonal growth; multiple twin¬ 
ning is very fine when present and is frequently absent. There is also 



58 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

present a little quartz, occasional ragged prisms of tourmaline, numerous 
rounded grains of titanite, and a little epidote. The thin section is crossed 
by several microscopic fractures, which branch in places and are filled 
chiefly with quartz and feldspar. 

The granite (Specs. 21 and 23) is a light gray, fine-grained rock, com¬ 
posed essentially of white feldspar, quartz, and a little black biotite, while 
small pink garnets can be identified in places. It is cut by occasional, 
irregular, segregation stringers of pegmatitic feldspar and quartz. Fine 
multiple twinning can sometimes be distinguished on the feldspars. In 
thin sections under the microscope, soda-lime feldspar is seen to be 
dominant with the potash feldspars (orthoclase and microcline) present 
in variable amounts; there are granophyric intergrowths of feldspar and 
quartz; and both the feldspar and quartz show fracturing and optical 
distortion. Biotite occurs in small flakes dark green to brown in color, 
and a little sericite is present as an alteration product of feldspar. Bagged 
prisms of tourmaline, and occasionally irregular grains of titanite, 
magnetite, and pyrite make up the accessory minerals. The quartz grains 
contain numerous fluid inclusions. 

In mineral composition this rock corresponds to a granodiorite and is 
closely similar to the granite (granodiorite) exposed in the quarry at 
Columbia, an analysis of which is given on page 65. The Elk Hill granite 
is finer grained and probably contains less quartz than the rock at 
Columbia. 

Passing northeast toward Elk Hill the granite bands become broader, 
less contorted, and more uniform in composition; and there is much less 
hornblende schist present. Near Elk Hill the schistosity has a strike of 
N. 45° E. and a dip of about 45° southeast. The granite exposed near 
Byrd Creek is similar to that in the Columbia area on the west side of the 
pegmatite belt. 

In places the hornblende schist contains much epidote, and about a 
mile southeast of Elk Hill some of the rock is composed almost exclusively 
of light green, granular epidote and white feldspar. In a thin section 
of this rock (Spec. 26), examined under the microscope, the epidote is 
largely in excess, occurring in irregular rounded grains, that look as though 
they might be primary. It is slightly pleochroic, changing from light 
yellowish-green to colorless. The feldspars are partly kaolinized but are 
probably all plagioclase. A little quartz and a few small grains of 
ilmenite, partly altered to leucoxene, make up the remaining minerals 
present. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


59 


Pegmatite Belt. 

GENERAL DESCRIPTION. 

The pegmatite belt can be traced across the area mapped, in a north¬ 
east and southwest direction, from Hadensville in Goochland County, to 
Cumberland, near the southern boundary—a distance of over 30 miles— 
and it extends for an unknown distance beyond the limits of the map. In 
width the belt varies up to nearly three miles, and perhaps more, for lack 
of exposure makes it difficult to locate the exact boundaries except in a 
few localities. 

While pegmatite is the dominant rock in this belt, there is also much 
interleaved granite, especially along the eastern side. North of James 
River, where the area was mapped in detail, the northwest contact of the 
pegmatite with the granite is sharply defined, but the other boundary is 
less definite, for the pegmatite apparently fingers out into the granite; 
and in many places the two rocks are so closely associated that it would 
be impossible to map them as separate units. In most of the specimens 
of granite obtained from the central portion of the pegmatite area, and 
examined microscopically, the potash feldspars are dominant over the 
soda-lime feldspars. Hornblende schists are practically absent; no out¬ 
crops were seen, and the few pieces of float found were near the border 
portions. 

The pegmatite area is one of low relief and there are few prominent 
outcrops. It seems to be less resistant to erosion than the granite, and 
this probably explains the location of Little Byrd Creek, which, through¬ 
out almost its entire length, is confined to the pegmatite belt. 

DETAILED DESCRIPTIONS. 

James River section .—The best rock exposures found in the pegmatite 
belt occur along the steep hills and bluffs that border the lowlands on the 
north side of James River. The railroad station at Island is near the 
center of the belt, which is here about 3 miles wide. The western boundary 
crosses the river midway between Columbia and Island, and is sharply 
defined; but the eastern boundary, which crosses the river near Byrd 
Creek, is less definite, for the pegmatite is more or less interleaved with 
biotite granite and the exposures are rather poor. 

Near the western boundary of the pegmatite belt, 1% miles northwest 
of Island, there are outcrops of coarsely crystalline pegmatite (Spec. 12-A) 
composed of pink orthoclase feldspar, quartz, and a little muscovite. The 


60 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

feldspar, which is dominant, occurs in irregular individuals ranging up to 
2 or 3 inches in diameter. The rock is slightly gneissic in structure, the 
strike the schistosity being northeast and southwest and the dip nearly 
vertical. 

In places the coarse pegmatite is interleaved with a fine-grained pegma¬ 
tite or granite (Spec. 12), similar in composition, and highly schistose. 
Examined under the microscope it is seen to be granitic in texture with 
occasional fine micrographic intergrowths of quartz and feldspar. Micro- 
cline is the dominant mineral, orthoclase being also present, while quartz 
and acid plagioclase feldspars occur in lesser quantities. The feldspars 
frequently show perthitic intergrowths and are partly kaolinized; the 
quartz contains irregular fluid inclusions, which occasionally hold moving 
bubbles; and both minerals have been more or less fractured and show 
some optical distortion. The muscovite is partly if not entirely secondary 
after feldspar. Magnetite, ilmenite partly altered to leucoxene, and titanite 
make up the minor accessory minerals. 

A coarse-grained, gneissic pegmatite, which outcrops half a mile west 
of Island, contains numerous red garnets, 1 to 2 mm. in diameter; other¬ 
wise it is similar to the rock previously described. In the vicinity of 
Island there is much biotite granite intermixed with the pegmatite. 

Little Byrd Creel ’.—For several hundred yards east of Little Byrd 
Creek, and about 214 miles northeast of Island, the road to Fife is crossed 
by alternating bands of pegmatite and granite, which vary in width from 
an inch up to several feet. The average strike is 1ST. 45° E. The pegma¬ 
tite (Spec. 71) is composed of pink potash feldspar, in individuals ranging 
up to 3 inches in diameter, quartz, a little muscovite, and a few dark red 
garnets, some of which are over half an inch in diameter. In places a 
graphic intergrowth of quartz and feldspar may be distinguished. Farther 
east the bands are somewhat contorted. 

Where the large branch crosses the road, half a mile west of Little 
Byrd Creek, a dark brown, fine-grained granite is exposed. It is about 50 
yards wide and has a strike of 1ST. 45° E. The rock (Spec. 70) is fine¬ 
grained, even-granular, except for occasional phenocrvsts of potash feldspar 
about 0.5 cm. in diameter, and is only slightly schistose. Examined under 
the microscope it is seen to consist of potash feldspar (chiefly orthoclase), 
soda-lime feldspar, quartz, biotite, muscovite, a little light brown horn¬ 
blende, a few scattered grains of magnetite or ilmenite, and occasional 
needle-like inclusions of rutile. The feldspar individuals, near their 
borders, frequently show granophyric intergrowths with quartz. The 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


61 


quartz grains contain numerous fluid inclusions, some of which hold 
rapidly moving bubbles. Both quartz and feldspar show fracturing and 
optical distortion. The muscovite is partly secondary after feldspar but 
some of it is probably primary. 

Lantana .—The contact between the pegmatite and granite crosses the 
road to Bula, 1% miles southeast of Lantana. The outcrops are much 
weathered but in places graphic intergrowths of feldspar and quartz can 
be seen. The pegmatite weathers to a white soil which is readily distin¬ 
guished from the gray, sandy soil of the granite and the dark red clay of 
the hornblende schist. 

Bula .—On the east side of the pegmatite belt, in the vicinity of Bula, 
the boundary is not very definite, for the pegmatite splits up into dikes 
that are separated by areas of granite. One of these dikes is located about 
half a mile southeast of Bula, and can be traced in a northeast and south¬ 
west direction for a mile or more. This pegmatite (Spec. 77) contains 
a large amount of muscovite mica, and flakes 2 or 3 inches in diameter 
are sometimes found on the surface. 

Shannon Hill .—The western boundary of the pegmatite belt crosses 
the Three Chop road about 2^ miles southeast of Shannon Hill. There 
are practically no outcrops along this ridge road, but an exposure of partly 
decomposed pegmatite was found in a recently opened ditch. The rock is 
a beautiful example of graphic pegmatite, being composed almost exclu¬ 
sively of feldspar and quartz, and shows little if any schistosity. 

Dickey farm .—On the farm of G. S. Dickey, 2 miles southeast of 
Cremona, there are several pits that were sunk in prospecting for gold. 
Natural exposures are few in this vicinity, but the country rock is partly 
a dark granite similar to Spec. 70, described on page 60. In the pits a 
dark blue, close-textured, siliceous rock is exposed, which appears to have 
been formed by silicification of the country rock, for it contains fragments 
of the granite that are only partly replaced by silica. The rock is exten¬ 
sively brecciated and has been recemented by white vein quartz. There 
are numerous vugs lined with quartz crystals and many of the veinlets 
show crustification. The minerals sphalerite, pyrite, chalcopyrite, and 
galena, are present in small amounts and may be identified in places; 
and assays are reported to show traces of gold and silver. The ore min¬ 
erals, at least in part, appear to be of later deposition than most of the 
quartz; in one specimen, sphalerite occurs filling a small cavity which is 
lined with quartz crystals. 


62 GEOLOGY OF THE GOLD BELT IN THE JAMES KIVER BASIN. 

Other localities .—Pegmatite is exposed at many places in Cumberland 
County along the strike of the pegmatite belt, but outcrops of fresh rock 
are rare, and all that were examined in detail show little variation from 
the occurrences described above. Pegmatite is exposed near Willis River, 
for a mile or two southwest of Flanagan Mills; it outcrops near Reynolds 
Creek, about 2 miles southeast of Trenton Mills, and again between Tally 
and Oak Forest; and there are numerous exposures in the vicinity of 
Cumberland, and near the southern boundary of the area mapped. 

Columbia Area. 

GENERAL DESCRIPTION. 

The Columbia granite area is bounded on the northwest by the meta¬ 
morphosed sedimentaries, chiefly pre-Cambrian in age, and on the south¬ 
east by the pegmatite belt; but much of the granite that occurs inter¬ 
leaved with the pegmatite and in the Elk Hill complex appear§ to be 
similar in mineral composition to the typical granite of the Columbia 
area, and probably has a common origin. 

In the Columbian area there is very little rock present corresponding 
in mineral composition to a true granite, in which orthoclase is dominant 
over the plagioclase feldspar. Almost everywhere soda-lime feldspars are 
in excess, and near the border portion of the rock and close to many of 
the areas of hornblende schist, the potash feldspars are entirely absent. 
Therefore the rock may more properly be called a granodiorite or quartz- 
diorite. Muscovite is not common; biotite is usually plentiful in the 
dominant and more acid facies of the rock, but in the southern portion of 
the area it is largely replaced by hornblende. 

Hornblende schists are of frequent occurrence in all portions of the 
area except in the north end of the tongue or embayment lying between 
Carysbrook and Wilmington; they become more plentiful near the contact 
with the old metamorphosed sedimentaries, where they commonly form a 
narrow belt separating the granite from the older rocks. In some places a 
gradation may be traced from granite into hornblende schist, but fre¬ 
quently the contact between the two is sharply defined. The areas of 
hornblende schist vary in size from a maximum of several square miles 
down to small masses, such as are usually called schlieren. 

In passing northward from James River toward Carysbrook and 
Wilmington, there is a gradual but very noticeable change, both in the 
mineral composition and in the texture of the rock. While the exposures 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


63 


are by no means continuous, outcrops are fairly plentiful along the bluffs 
of Rivanna River, and nowhere is there any evidence of sudden change 
such as would be expected if there were rocks present belonging to different 
periods of intrusion. 

South of James River, soda-lime feldspars greatly predominate over 
the potash feldspars, which are frequently absent; most of the rock is 
hornblendic rather than biotitic; and the areas of hornblende schist are 
common. Passing northward toward Carysbrook the potash feldspars 
become more abundant though they are usually subordinate to the plagio- 
clase; hornblende is rarely present in the granite, while biotite which is 
plentiful near the river becomes relatively scarce; and no areas of horn¬ 
blende schist were found northwest of Rivanna Mills. The change is 
therefore one of decreasing basicity, and of decreasing percentages of the 
minerals that commonly crystallize out first. 

In the vicinity of James River the granites are even-granular in 
texture but passing northward they become porphyritic and contain plieno- 
crysts of feldspar. These plienocrysts are frequently bent and broken, the 
fractures as well as the interstitial spaces being filled with minerals of 
later crystallization; and this indicates that differential movements took 
place in the magma after crystallization had commenced and before the 
rock had completely solidified. The occurrence of masses of coarse¬ 
grained granite surrounded by rock of finer texture, such as may be seen 
in the quarry a mile northwest of Carysbrook (see description, pages 75-77), 
is probably due to the same causes. 

The granite south of James River is highly schistose; the rocks exposed 
in the vicinity of Fork Union and Rivanna Mills are much less affected, 
wdiile north of Carysbrook the granite is almost massive. 

Pegmatite dikes are plentiful near Rivanna Mills, but were not noted 
elsewhere in the Columbia area. These pegmatites show little or no 
evidence of schistosity. 

All of the facts outlined above lead to the same conclusions, namely, 
that the granite in the north end of the embayment between Carysbrook 
and Wilmington solidified later than the rock in the remainder of the 
area; that important differential movements took place while this latex- 
granite was in process of crystallizing; and that the magma from which 
the latter solidified was probably residual from the crystallization of the 
older rocks. 


64 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


DETAILED DESCRIPTIONS. 

Columbia ..—The Cowherd quarries,® located on the north side of James 
River at Columbia, and lying partly in Goochland County and partly in 
Fluvanna County, furnish the best exposures of fresh granite that are to 
be found in the Columbia area. These quarries were first opened when 
the James River canal was in service, but in recent years little work has 
been carried on, and since 1900 all operations have been suspended. 

The rock is of medium dark-gray color, fine-grained, even-granular, 
and very schistose, with fine, straight banding. The minerals distin¬ 
guishable megascopically are white, glassy quartz and feldspar, black 
biotite, a few, light green grains of epidote, which are for the most part 
closely associated with the biotite, and occasional small pink garnets. 
Multiple twinning can be distinguished on some of the feldspars with the 
aid of a pocket lens. 

The strike of the schistosity is U. 45° E. The vertical joints are 
widely spaced, intersecting the rock in three or more directions, and the 
joints parallel to the surface are spaced 2 to 3 feet apart in some of the 
deeper exposures. The granite is cut by numerous quartz veins which 
usually carry a little biotite. They vary from a fraction of an inch up to 
2 feet in width, and run in all directions, though most of them are 
probably parallel to the schistosity. The fact that fractures frequently 
intersect the veins in directions coincident with the schistosity indicates 
that they were formed before the cessation of the period of deformation. 6 
The presence of biotite and, occasionally, of a little muscovite and feldspar, 
are additional evidence of the early formations of the veinlets and of 
their probable magmatic origin. 

Examined in thin section (Spec. 240) under the microscope the rock 
is seen to be composed of the following minerals, the order given being 
that of relative abundance—quartz, soda-lime feldspar (oligoclase), pot¬ 
ash feldspars (chiefly microcline), biotite, muscovite, epidote, garnet, cal- 
cite, zircon, and apatite. Under low magnification the schistosity is 
distinct; most of the mica shows parallel orientation and the segregation 
of the quartz into bands is so pronounced that in places they resemble 
veinlets. This fact suggests that some of the quartz veinlets exposed in 
the quarry may have been formed by segregation through fractional crystal¬ 
lization during the solidification of the granite. 

oWatson, Thomas L., Granites of the Southeastern Atlantic States, Bull. U. S. 
Geol. Survey, No. 426, 1910, pp. 112-113. 

bWatson, Thomas L., Ibid., p. 113. 




DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


65 


The quartz is present in large clear individuals that in places show a 
slightly wavy extinction; liquid- and gas-filled cavities are common, 
occurring partly in irregular shapes, and partly in small oval or rounded 
forms that are arranged in long rows or planes. 

The soda-lime feldspar, which is dominant over the potash feldspars, 
shows rather coarse twinning after the albite law; the potash feldspar is 
nearly all microcline and there is only a little orthoclase present. Grano- 
phyric intergrowths of feldspar and quartz are fairly plentiful. 

Biotite occurs in small dark green flakes showing strong absorption, 
and the white mica present is partly if not entirely secondary after 
feldspar. The epidote is in small, irregular light green to colorless grains, 
which are more plentiful wherever the biotite is abundant and are absent 
in areas containing little biotite. 

Small pink garnets are scattered through the thin section; they are 
frequently fractured and broken, and seldom show good crystal form. The 
small amount of calcite present is evidently secondary. Numerous small 
idiomorphic crystals of zircon, and occasional apatite needles, are present 
as inclusions in the quartz and feldspar. 

In mineral composition the rock is intermediate between granite and 
quartz-diorite. In the quantitative system of classification of igneous 
rocks it falls in class 1, order 3, rang 3, and subrang 4. A complete 
chemical analysis made from an average sample of the granite exposed in 
the quarry is given below. 

Analysis of granite from Cowherd quarry, Columbia. 


(Dr. Roger C. Wells, analyst.) 


SiO, . 

AlA . 

Fe 2 0 3 . 

FeO . 

MgO . 

CaO . 

. 72.43 

. 13.93 

. 0.90 

. 2.45 

. 0.58 

. 3.38 

Na.O . 

. 3.20 

k„6 . 

. 2.14 

HoO . 

. 0.11 

h"o+ . 

. 0.54 

r nn . 

. 0.21 

7i-n 

co, . 

. 0.09 

p„0, . 

. 0.04 

s . 

. 0.01 

MnO . 

. 0.02 

BaO . 

. 0.01 

SrO . 





100.04 






















66 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

About a. quarter of a mile northwest of the quarries described above, 
and on the east side of the Stage Junction road as it leaves Columbia, a 
fresh surface of granite is exposed by recent blasting. The rock is cut 
by irregular veinlets of quartz some of which contain biotite mica; and 
there are also veinlets of coarsely crystalline calcite ranging up to 2 inches 
in width. 

Megascopically the rock (Spec. 5) is similar to the granite described 
above, excepting that the gneissic banding is slightly more prominent. 
Under the microscope the chief difference is in the relative proportion of 
the feldspars, orthoclase and microcline being present in very subordinate 
amounts. White mica is practically absent and there is a little hornblende 
present, dark green to bright blue in color. Ilmenite, partly altered to 
leucoxene, occurs as a minor accessory constituent. 

Passing northward along the Stage Junction road bands of hornblende 
schist begin to make their appearance at a distance of half a mile from 
Columbia. At first these bands or schlieren are only a few feet wide, but, 
as the contact with the sedimentaries is approached, they become larger 
and more plentiful until, within 400 or 500 yards of the contact, the 
granite completely disappears. There is also a change in the direction of 
the schistosity; near Columbia it has a strike of approximately N. 45° E., 
but near the sedimentaries the schistosity runs N. 15° W., and appears to 
be parallel to the contact. These areas of hornblendic rocks occur through¬ 
out most of the Columbia granite area, but they are much more plentiful 
in the vicinity of the borders. 

About 114 miles east of Columbia there is a large rock exposure show¬ 
ing a gradation of the granite into hornblende schist. The schistosity 
varies from N". 20° to 40° E. The belt of hornblende schist is elongated 
parallel to the schistosity—the width being about 200 feet, and the length 
indeterminable because of the lack of sufficient exposures. 

Specimen 6, taken more than 100 feet west of the belt of schist, is 
intermediate in character, but in the hand specimen is almost indistin¬ 
guishable from the typical Columbia granite. The rock is dark gray in 
color, fine-grained, and shows a well-developed gneissic banding. It is 
composed essentially of quartz, feldspar, biotite, black hornblende, which 
is very difficult to distinguish megascopically from the biotite, small pink 
garnets, and a little epidote. 

Examined under the microscope, soda-lime feldspar seems to be 
dominant over quartz, the potash feldspars are absent, and the hornblende 
is equal to or in excess of biotite. The feldspar frequently shows twinning 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


67 


according to the pericline as well as the albite law; the quartz contains 
numerous fluid inclusions arranged in long lines or planes; and the horn¬ 
blende is brown to dark green in color, and shows occasional idiomorphic 
outlines with perfect cleavage. Small, well-formed, pink garnets, a few 
grains of light green to colorless epidote, and, rarely, small idiomorphic 
crystals of zircon make up the minor accessory minerals. 

Specimen 7 was taken from the outcrop about 30 feet northeast of the 
rock just described. It is finer grained than specimen 6, and contains 
more hornblende, much of which is concentrated in narrow streaks or 
schlieren. Under the microscope, plagioclase feldspar is seen to be 
dominant over quartz, and there is no potash feldspar or white mica 
present. The feldspars show twinning after the pericline as well as the 
albite law, and some of them contain peculiar inclusions of feldspar or 
quartz, which are present in alternate bands of the albite twinning. These 
inclusions are in the form of narrow parallel bands, which are oriented at 
an angle of 30° to the twinning planes, and they all extinguish simul¬ 
taneously. The hornblende is strongly pleochroic in shades of dark green, 
blue, and greenish-brown. The biotite is light brown to green in color and 
is not nearly so plentiful as the hornblende. Garnet in fairly well formed 
crystals, irregular grains of epidote, ilmenite, and small inclusions of zircon 
make up the minor constituents. 

About 110 feet east of the specimen just described, the rock (Spec. 8) 
contains flat, bladed crystals of black hornblende, ranging up to 1 cm. in 
length, embedded in a medium-grained ground-mass of feldspar and quartz. 
With increase of hornblende there is a corresponding decrease of biotite, 
and portions of the rock are almost free of mica. The garnets are like¬ 
wise larger in this rock, some of them being nearly 0.5 cm. in diameter. 
The larger size of some of the minerals, especially the hornblende, may 
have been caused by a partial resolution before complete solidification had 
takn place, followed by continued crystal growth. 

Microscopically, soda-lime feldspar is the dominant mineral and there 
is no potash feldspar or white mica present. Both albite and pericline 
twinning are common. Quartz is the second mineral in relative abundance 
and contains numerous irregular fluid-filled cavities. Dark green horn¬ 
blende is the principal ferromagnesian mineral, only a little brown biotite 
being present. The remaining accessory minerals are garnet, in numerous 
well-formed crystals, epidote, ilmenite partly altered to leucoxene, pyrite 
partly altered to limonite, and small included grains of titanite and zircon. 

Specimen 9, taken from a point 30 feet southeast of the rock last 
described, is a typical quartz-diorite schist. It is a dark gray, medium- 


68 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

grained rock in which black hornblende, and white quartz, and feldspar 
are the only minerals distinguishable megascopically. Under the micro¬ 
scope plagioclase (probably andesine) is seen to be dominant, but dark 
green hornblende is almost as abundant as the feldspar. Quartz, a little 
epidote, and a few small, scattered grains of ilmenite make up the remain¬ 
ing constituents. Both quartz and feldspar show considerable optical 
distortion and some fracturing. 

Specimen 10 was taken 80 feet farther northeast. Megascopically it 
is similar to specimen 9, but contains more hornblende and is darker 
colored, being almost black. Examined microscopically no feldspar could 
be distinguished. The minerals present in the order of their relative 
abundance are hornblende, quartz, epidote, chlorite, and a few scattered 
grains of ilmenite. 

About 100 feet to the east there is an outcrop of greenish-gray, talcose 
schist, which probably represents an alteration product of the amphibolite 
schist described above. In thin section (Spec. 11) under the microscope, 
the rock is seen to consist of needle-like crystals of secondary hornblende, 
light green to almost colorless talc, a little chlorite, and numerous small 
grains of magnetite. 

Near the large creek 2 miles southwest of Columbia there is much 
quartz lying loose on the surface and these pieces contain much musco¬ 
vite, and occasionally miarolitic cavities lined with poorly formed crystals 
of quartz, feldspar, and muscovite. Some of the mica shows well-developed 
hexagonal shapes. 

On the road to Lantana, hornblende schists are first encountered about 
half a mile northeast of Columbia, and, continuing northeastward, the 
occurrences increase in number and extent, until in the vicinity of the 
contact, little granite is to be found. The contacts between the areas of 
hornblende schist and the granite are commonly sharp and well defined, 
but in many places rocks occur that are intermediate in mineral com¬ 
position. 

Big Byrd Creek .—On the east side of Big Byrd Creek, near the contact 
between the granitic rocks and the altered sedimentaries, there is an out¬ 
crop of rock which is intermediate between the granite and the typical 
hornblende schists. 

It is a dark gray, fine-grained gneiss (Spec. 29) composed essentially 
of feldspar, hornblende, quartz, and biotite. Examined microscopically the 
feldspar is seen to be all plagioclase; multiple twinning is frequently 
absent, and as the index of refraction is close to that of quartz, there is 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


69 


difficulty in distinguishing between the two minerals. The hornblende 
crystals are strongly pleochroic, ragged in outline, and contain numerous 
inclusions of quartz, feldspar, and epidote. The biotite, which is partly 
altered to chlorite, is not plentiful. Ilmenite occurs in irregular grains 
scattered through the rock, and shows partial alteration to leucoxene. 

Lcintana .—A peculiar variety of the hornblende schist was found about 
l 1 /^ miles southeast of Lantana. The minerals recognizable megascopically 
are black hornblende and a little fine-grained, white feldspar. The horn¬ 
blende crystals are frequently stained a deep red color, and the contrast 
between the black, red, and white gives the rock a very striking appearance 
in the hand specimen (93). Examined microscopically it is seen to consist 
of hornblende, basic plagioclase, epidote, quartz, magnetite partly altered 
to limonite, and a few small grains of rutile. 

About 2*4 miles northeast of Lantana the pegmatite belt approaches 
within less than 400 yards of the altered sedimentaries, and the inter¬ 
vening space is largely occupied by hornblende schists. At this point the 
biotite granite is absent, being replaced by a hornblende-bearing rock 
(Spec. 99), which closely resembles a granite in appearance, but contains 
no potash feldspar. It is a medium, dark gray, gneissic rock, composed of 
quartz, acid plagioclase, hornblende, and garnet, with lesser amounts of 
magnetite, zircon, and titanite. Some of the feldspar is unstriated and 
difficult to distinguish microscopically from quartz, which it resembles in 
refraction and birefringence. The hornblende is dark green to bluish-green 
in color, strongly pleocliroic, and shows fairly good cleavage. Pink garnets 
are very plentiful, and the larger ones contain numerous inclusions of 
quartz and magnetite. 

Passing northeast from the locality just described, the lack of exposures 
makes it difficult to trace the exact contact between the granite area and 
the metamorphosed sedimentaries; and this difficulty is increased by the 
uncertainty as to the igneous or sedimentary origin of some of the rocks 
in the immediate vicinity of the contact. 

Granite is exposed in the branch near the private road, less than a 
mile northeast of the Young American mine. It is a light gray, fine¬ 
grained rock (Spec. 105), composed chiefly of quartz and feldspar, with 
minor amounts of biotite. Under the microscope the feldspar is seen to be 
plagioclase (probably andesine), but, as much of it is unstriated, it is 
distinguishable from quartz with difficulty. The rock contains a little 
sericite, ilmenite partly altered to leucoxene, and occasional small inclu¬ 
sions of rutile, titanite, and zircon. 


70 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

Tabscott .—Granite and hornblende schist outcrop together near the 
branch half a mile northeast of the locality last described and about 1% 
miles south of Tabscott. The granite (Spec. 108) is a light gray, fine¬ 
grained rock, gneissic in structure, and composed for the most part of 
quartz, feldspar, and small flakes of light green chlorite. Examined 
microscopically the feldspars are seen to be chiefly acid plagioclase, with 
only a little orthoclase present; granophyric intergrowths with quartz 
are common; and in places the feldspars show alteration to sericite. 
Ilmenite occurs in small grains that usually show alteration to titanite or 
leucoxene. The alteration to titanite is more common and there are many 
grains of the latter scattered through the rock. 

The hornblende schist (Spec. 109) is dark bluish-gray in color, and 
usually fine-grained. The hornblende, which is dominant, occurs in 
slender, prismatic crystals, that are dark green in thin sections, and fre¬ 
quently show idiomorphic outlines and perfect cleavage. Quartz and un- 
striated plagioclase feldspar (probably andesine) fill the interstices between 
the hornblendes. Ilmenite and rutile are prominent accessory constituents, 
occurring as included grains in all of the other minerals, though they are 
not so plentiful in the hornblende. There are also numerous grains of 
titanite present, probably secondary after the other titanium minerals, 
and small crystals of zircon occur as inclusions in the quartz. 

A similar, but slightly coarser-grained, hornblende schist outcrops in 
the road iy 2 miles southwest of Tabscott. The rock (Spec. 215) is com¬ 
posed of hornblende, quartz, unstriated plagioclase (oligoclase or andesine), 
a little epidote, and numerous grains of titanite, some of which contain 
small inclusions of rutile. In these schists the hornblende crystals have a 
strong tendency to lie with their columnar directions almost parallel, and 
it is this that gives the rock its schistosity. The strike of the schistositv 
is N. 51° E. 

Payne farm .—On the Payne farm, iy 2 miles southeast of Tabscott, 
there is a number of old pits or quarries from which the Indians obtained 
steatite. These openings are surrounded by pieces of broken bowls which 
were ruined in the process of making. Kecently, sawed slabs of this rock 
have been used to line the fire boxes of boilers, at some of the mines in 
the vicinity, and it is said to have proved very satisfactory for the purpose. 

The rock (Spec. 107) is greenish-gray in color and in places contains 
small crystals of magnetite and pyrite. Under the microscope it is seen to 
consist largely of talc and needle-like crystals of secondary hornblende. There 
are also a few fragments of unaltered hornblende which may be primary, 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


71 


much chlorite, and a little magnetite or ilmenite, and titanite. The rock 
is evidently derived from a basic igneous rock, probably from the horn¬ 
blende schists. A similar occurrence is described on page 68. 

Some of the rock in this vicinity contains a greater percentage of horn¬ 
blende than the specimen described above, and other pieces were found that 
consist exclusively of bright green cleavable chlorite. 

Trent farm .—On the south side of James River, in the southern portion 
of the Columbia area, the rocks are apparently more basic in composition, 
potash feldspars are practically absent and hornblende is often more 
prominent than biotite. On the farm of S. W. Trent, 3 miles southwest of 
Hatcher, hornblende schist occurs in the vicinity of the contact. The rock 
is dark gray to black in color, with a highly lustrous fracture, due to the 
presence of much hornblende having approximately parallel orientation. 
The minerals present, in the order of their relative abundance, are pris¬ 
matic hornblende, feldspar, quartz, and a little epidote. The feldspar is 
all plagioclase, corresponding to labradorite in extinction angle and index 
of refraction, and much of it is unstriated. 

Passing northwest as far as Hatcher, hornblende is a prominent con¬ 
stituent in most of the rocks found; in places it is dominant over the 
other minerals, forming the typical hornblende schists, but elsewhere 
feldspar is dominant, and the rocks correspond to diorites and quartz- 
diorites in composition. On the whole hornblende appears to decrease in 
abundance with distance from the contact. The same statement holds 
true for the rocks that are exposed between Lawford and the contact. 

Trenton Mills .—On the west side of Willis River, in the vicinity of 
Trenton Mills, there is a large area of hornblende schist, possibly 2 or 3 
square miles in extent. The rock is medium-grained and highly schistose, 
the color varying from gray to black according to the amount of feldspar 
and quartz present. The darker varieties are composed almost exclusively 
of hornblende. 

New Canton .—In some of the branches 3 or 4 miles south of Hew 
Canton a hornblende granite or quartz diorite is exposed, which contains 
a few large flakes of dark brown biotite and small pink garnets. A short 
distance east of the county road and 1% miles south of Hew Canton a light 
gray, gneissic rock (Spec. 300) is exposed which consists essentially of 
feldspar, quartz, biotite, and muscovite. 

Examined under the microscope no potash feldspar could be identified. 
The plagioclase has an index of refraction slightly below quartz, approxi¬ 
mately corresponding to oligoclase in composition, and frequently shows 


72 GEOLOGY OF THE GOLD BELT IN THE JAMES EIVER BASIN. 

twinning after the albite and pericline laws, but much of it is unstriated. 
The biotite is brown to green in color and the muscovite is partly if not 
entirely secondary in origin. A little chlorite and epidote are present, 
but other accessories are rare. 

Stearnes .—Near the Chesapeake and Ohio Eailroad, 2 miles northeast 
of Stearnes and 4 miles southwest of Columbia, the granite (Spec. 14) 
is light gray, fine-grained, and shows distinct gneissic banding. Occa¬ 
sional phenocrysts of feldspar showing Carlsbad twinning can be distin¬ 
guished in the hand specimen. This is one of the few localities in the 
Columbia area where the rock is a true granite in mineral composition. 
The minerals present, in the order of their relative abundance, are potash 
feldspar (chiefly microcline), soda-lime feldspar (oligoclase), and quartz; 
a little biotite, muscovite, calcite, and epidote; and lesser amounts of 
garnet, titanite, ilmenite, leucoxene, and zircon. 

Microcline showing beautiful crossed twinning is the dominant mineral 
and orthoc-lase seems to be practically absent. Oligoclase, which is the 
second mineral in relative abundance, shows occasional twinning after the 
pericline as well as the albite law, and microperthite is fairly plentiful. 
Micrographic intergrowths with quartz are common. The biotite is dark 
green to brown in color and not very abundant; the flakes are usually 
oriented parallel to the schistosity of the rock. The white mica appears 
to be entirely secondary after feldspar, but there may be some primary 
muscovite present. It does not show the same uniformity of orientation 
that is exhibited by the biotite. Calcite is unusually abundant and is 
probably secondary after plagioclase. Epidote occurs in small grains, being 
more plentiful where the biotite is most abundant, and is undoubtedly 
secondary in origin. The garnets contain numerous small inclusions of 
quartz. Titanite is common and in places contains included grains of 
ilmenite, from which it may have been derived. The ilmenite grains 
occasionally show partial alteration to leucoxene. 

For a mile northeast of Stearnes hornblende schist is exposed in the 
bluffs along the railroad. It is a fine-grained, dark bluish-gray rock, com¬ 
posed of small black prismatic crystals of hornblende, showing approxi¬ 
mate parallel orientation, and white plagioclase and quartz. The contact 
with the granite on the northwest side of the schist is well exposed. It is 
sharply defined, without evidence of gradation, and has a strike of 
N. 45° E. 

Near Stearnes the hornblende schist is cut by narrow bands of siliceous 
rock 2 to 3 inches in thickness. This rock (Spec. 16) is fine-grained. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


73 


light gray in color, and closely resembles a quartzite in texture and appear¬ 
ance. Small pink garnets and needles of dark green hornblende are 
present in places, and some of the rock contains much fine-grained mag¬ 
netite. A thin section examined under the microscope contains irregular 
rounded grains of quartz, many idiomorphic crystals of magnetite, a few 
scattered prisms of dark green hornblende showing occasional crystal out¬ 
lines, a little plagioclase feldspar, sericite, and small inclusions of titanite 
and zircon. The quartz contains numerous fluid inclusions. 

Fork Union .—The contact between the granite and the metamorphosed, 
pre-Cambrian sedimentaries passes through the town of Fork Union. 
Granite is exposed in the road about half a mile southeast of the town. 
It is a medium-grained, light gray rock, containing flakes of biotite 2 to 3 
mm. in diameter, and is much less schistose than the rocks previously 
described. 

Examined in thin section (Spec. 50 ) a under the microscope, potash 
feldspar (chiefly microcline) appears to be dominant over soda-lime 
feldspar, but the rock is so badly altered that it is impossible to deter¬ 
mine their relative proportions. Micrographic intergrowths with quartz 
are common. Both quartz and feldspar show fracturing and strain 
shadows. The biotite occurs in greenish-brown flakes showing strong 
absorption. The feldspars and biotite are extensively altered with the 
production of epidote, a little chlorite, and some sericite, as the principal 
secondary minerals. Reddish-brown prisms of tourmaline 1.5 mm. or 
more in length are occasionally present, and rutile needles are abundant 
especially in some of the biotite. Fluid inclusions are common in the 
quartz grains. 

A similar granite, occurring at the Snead mine a mile north of Fork 
Union, is described on page 181. 

Rivanna Mills .—On the farm of H. Williams, half a mile north of 
Rivanna Mills, granite was formerly quarried to furnish stone for the dam 
and canal locks. This rock is medium dark gray in color and porphyritic 
in texture, containing eyes of feldspar that range up to nearly 1 cm. in 
diameter. The minerals recognizable megascopically are feldspar, quartz, 
biotite, a little muscovite, and, rarely, small grains of pyrite. Some of the 
feldspar phenocrysts show fine multiple twinning. The schistosity is well 
developed, but is not nearly so pronounced as in the granites exposed in 
the section along James River. 


aThis thin section was made from a specimen collected by Dr. T. P. Maynard. 



74 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

An average sample of partly decomposed granite, from an outcrop 100 
yards east of Mr. Williams’ house, upon assaying yielded 0.015 ounces of 
gold per ton (see pp. 220-221). The sample was taken after several inches 
of the partly decomposed rock had been removed in order to prevent con¬ 
tamination. 

Dikes of pegmatite and aplite occur cutting the granite at several 
points on the Williams farm, and these rocks show very little if any 
evidence of schistosity. One of these dikes, located about 600 yards north¬ 
east of the house, is exposed in a prospect shaft 15 feet in depth. It 
has a strike of N. 15° E. and dips northwest at an angle of 45°. The 
pegmatite near the walls of the dike (see fig. 3) is fine-grained, and 
composed for the most part of feldspar and quartz, with only a little 
muscovite. The central portion of the dike consists chiefly of quartz 
carrying more or less feldspar and containing occasional coarse crystals 
of pyrite. Picked specimens of this quartz are said to have assayed nearly 
$3.00 gold per ton. 



SCALE 

0 1 2 3 4 Feet 

*- —i < --i i 


Fig. 3.—Vertical section showing pegmatite dike cutting granite near Rivanna Mills. 
G, granite; P, fine-grained pegmatite; Q, quartz with a little feldspar and pyrite. 









DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


75 


South of Rivanna Mills and also in the road three-quarters of a mile 
to the east there are numerous exposures of hornblende schist, and in the 
latter locality they are occasionally cut by small pegmatite dikes. 

Carysbrook bridge .—On the east side of Rivanna River, 150 yards below 
the road leading from Carysbrook to Wilmington, there is an exposure of 
granite (Spec. 61) containing feldspar phenocrysts ranging up to 1.5 cm. 
in diameter. The rock contains much less biotite than most of the granites 
previously described, and is only slightly schistose. 

Examined under the microscope, acid plagioclase is seen to be dominant 
with only minor quantities of orthoclase present. The feldspars show 
twinning after the albite, Carlsbad, and pericline laws, and in places there 
are micrographic intergrowths with quartz. The larger individuals fre¬ 
quently show evidence of having been bent and broken prior to the com¬ 
plete solidification of the rock, for the fractures are filled with minerals 
of later crystallization. The feldspars have been extensively altered to 
epidote, which is present in irregular rounded grains and in granular 
aggregates. The quartz contains rutile needles, imperfect zircons, and 
numerous fluid inclusions some of which show moving bubbles. There is 
also a small amount of light brown biotite present, but it is largely altered 
to chlorite. Pyrite is of occasional occurrence in small, cubical crystals, 
which show more or less alteration to limonite. 

A specimen (60) of the granite obtained about 20 yards above the 
Carysbrook bridge is typical of most of the rock in this vicinity. It is 
slightly schistose in structure, the feldspars are gray in color, and the 
biotite is not very plentiful. 

In thin section under the miscroscope it is seen that soda-lime feldspars 
(probably oligoclase) are dominant over the potash feldspars (orthoclase 
with a little microcline). The larger feldspars are frequently bent, or 
ruptured and faulted, and in some cases the fractures are filled with min¬ 
erals of later crystallization, indicating that there were probably differ¬ 
ential movements in the magma after crystallization had commenced and 
before the rock had completely solidified. The feldspars show twinning 
according to the albite, Carlsbad, and pericline laws, and they are more 
or less altered with the production of sericite, kaolin, epidote, and a little 
calcite. Biotite is present in small light green flakes partly altered to 
chlorite. The quartz contains numerous fluid inclusions and occasionally 
moving bubbles. Tourmaline is of sparing occurrence in light brown 
crystals with ragged outline. 

Carysbrook .—A quarry, opened in the granite to obtain rock for use 
in building the railroad, is located on the south side of Rivanna River, at 


76 GEOLOGY OF THE GOLD BELT IN THE JAMES KIVER BASIN. 

the Virginia Air Line railroad bridge, a mile northwest of Carysbrook. 
This quarry is within 100 yards of the contact between the granite and a 
chloritic slate which lies on the west. 

The rock exposed in the quarry is exceedingly variable in appearance; 
there are irregular areas or blotches of coarse-grained granite, ranging up 
to a foot or more in diameter, which are surrounded by a ground-mass of 
finer material; and the entire rock-mass is cut by irregular fractures 
running in every conceivable direction. Differential movements have taken 
place along some of these fractures, resulting in the formation of slicken- 
sided surfaces and the production of a little light green chlorite. 

The masses of coarse-grained granite are composed essentially of 
feldspar, quartz, and biotite, with a little pyrite in places. Some of the 
feldspars are 1 cm. in diameter, but the larger ones are frequently frac¬ 
tured and broken. They are white to light gray in color and occasionally 
show coarse multiple twinning. The biotite flakes, which range up to 0.5 
cm. in diameter, have no regular orientation, and the rock shows little 
evidence of regular schistosity. In places the rock is cut by narrow vein- 
lets, 1 to 2 mm. wide, which are largely composed of feldspar similar to 
that of the inclosing granite. i 

The fine-grained facies of the rock contains little or no biotite, con¬ 
sisting chiefly of feldspar and quartz; and as it has a uniform light gray 
color it is difficult to distinguish between the two minerals. A little calcite 
occurs in places along some of the fracture lines. 

Some of the granite found in the quarry and at other localities in the 
vicinity contains feldspars that are pink instead of gray in color, but this 
difference is probably due to alteration with the production of some ferric 
oxide, as the pink and gray varieties of rock are apparently similar in other 
respects. 

A thin section of the coarse-grained, gray granite was examined under 
the microscope/' The feldspars occur in large individuals, ranging up to 
5 or 6 mm. in diameter, and are frequently fractured and faulted, while 
the fissures as well as the interstitial spaces are filled with minerals of 
later crystallization, chiefly quartz and feldspar. Soda-lime feldspar 
(oligoclase?) is probably dominant over the potash feldspars (orthoclase 
with less microcline), but the latter are abundant, and in places may equal 
the former. The plagioclase shows fine multiple twinning and is much 
altered by kaolinization, while calcite is also present as a secondary product. 

“This thin section (Spec. 18) was made from a specimen collected by Dr. J. S. 
Grastv. 



DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


77 


Liquid- and gas-filled cavities occur in some of the fresher feldspars and 
are abundant in the quartz. Quartz is not as plentiful as in the granites 
near the James River section. A few of the individual grains show optical 
distortion and fracturing, but most of them show no pressure effects. 
Biotite occurs in brownish-green flakes that are of later formation than 
most of the feldspar, and in places appears to have partly replaced potash 
feldspar. Chlorite is also present, probably as an alteration product of 
biotite. Pyrite is one of the minor accessories, occurring frequently in 
association with biotite—often along the cleavage planes. Ilmenite, partly 
altered to leucoxene, is present in small grains. 

The thin section is crossed by a number of narrow, branching veinlets 
composed of fine-grained feldspar and quartz, with a little biotite and 
chlorite. These veinlets cut directly across the larger feldspars and other 
minerals. 

A thin section of the pink granite, which was examined under the 
microscope, shows no essential difference from the rock described above. 
The feldspars have undergone greater kaolinization, the biotite is entirely 
altered to chlorite, and there is a little hornblende present, part if not 
all of which is secondary. A few ragged crystals of reddish-brown tourma¬ 
line, a little magnetite or ilmenite, and scattered grains of titanite are 
among the minor constituents. The rock is cut by narrow, branching 
fractures filled with dark green chlorite. 

Granite similar to that exposed in the quarry extends southward 
beyond Carysbrook, and in the railroad cut half a mile south of the station, 
Ordovician sediments may be seen lying upon the eroded surface of the 
granite. Most of the rock is badly decomposed, but all fresh specimens 
seen were nearly massive in texture. The granite in this vicinity is essen¬ 
tially the same as the rock exposed at Carysbrook bridge (see description 
of Spec. 60, p. 75) excepting that the latter is markedly schistose. 

Gold Hill Granite Area. 

GENERAL DESCRIPTION. 

The Gold Hill granite area lies between Kent’s Store and Tabscott, in 
the northeastern portion of the region mapped. A general description of 
the area is given under the discussion of the country rock in the vicinity 
of the Gold Hill vein system (see pp. 176-177), and therefore will not be 
repeated here. 



78 GEOLOGY OF THE GOLD BELT IN THE JAMES BIVER BASIN. 

DETAILED DESCRIPTIONS. 

McGloam mine .—The granite (Specs. 161 and 166) exposed on the 
dumps at the McGloam mine is typical of much of the rock in the Gold 
Hill area. It is light gray, fine-grained, even-granular, and the minerals 
distinguishable megascopically are feldspar, quartz, small flakes of dark 
green chlorite, a little sericite, numerous cubes of pyrite, and occasional 
grains of magnetite. 

Examined under the microscope the rock is seen to vary from granitic 
to granophyric in texture. The feldspar is probably chiefly acid plagio- 
clase, but twinning can seldom be distinguished. Orthoclase is also present 
and fine intergrowths of feldspar and quartz are plentiful. A little biotite 
occurs in the rock, but most of it seems to have been altered to chlorite. 
Sericite and calcite are fairly abundant as secondary minerals, probably 
derived from feldspars. The minor accessories include pyrite, magnetite, 
zircon, leucoxene, apatite, and rutile needles. Fluid inclusions are common 
in some of the quartz grains. 

This rock, which is fairly representative of the granite in the Gold Hill 
area, differs from the granites previously described in being finer-grained, 
with a greater development of micrographic intergrowths of quartz and 
feldspar, and in having no schistosity. It contains less biotite and a rela¬ 
tively larger proportion of some of the minor accessories, such as pyrite 
and magnetite. 

Pieces of hornblende schist are present on the dump of the incline 
shaft, but the schistosity is not so well developed as in most of the horn¬ 
blende schists of the district. The rock (Spec. 167) is dark green in color 
and rather coarsely crystalline, containing bladed crystals of hornblende 
that range up to 1 cm. in length. The other minerals distinguishable 
megascopically are white feldspar and quartz, a little chlorite, and 
numerous small grains of magnetite and pyrite. Under the microscope 
it is seen that the hornblende is irregular in outline and contains numerous 
inclusions of quartz and feldspar, and in places there are graphic inter¬ 
growths of quartz and hornblende. The feldspar is unstriated plagio- 
clase, probably albite. A little chlorite is present as an alteration product 
of hornblende, and rutile needles occur in some of the quartz grains. 

Another variety of rock (Spec. 165) present on the dump is a chlorite 
schist containing scattered cubes of pyrite 2 to 5 mm. square, and octa¬ 
hedrons of magnetite ranging up to 2 mm. in diameter. Examined under 
the microscope, the chlorite is seen to be secondary from hornblende, of 
which many unaltered fragments remain. Aside from the alteration of 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


79 


hornblende to chlorite, the rock is essentially the same as the hornblende 
schist described above. 

Big Byrd Creek .—On the road, a quarter of a mile north of Big Byrd 
Creek and 1 miles southeast of Kent’s Store, there is an outcrop of 
greenish-gray granite (Spec. 82), which is slightly coarser-grained than 
most of the rock in the Gold Hill area. Some of the feldspars are 2 or 3 
mm. in diameter, and multiple twinning can occasionally be distinguished 
with the naked eye. Other minerals which may be identified in the hand 
specimens are quartz, chlorite, magnetite, garnet, and pyrite. 

Under the microscope the rock is seen to be composed almost entirely 
of micrographic intergrowths of feldspar and quartz, the feldspar consist¬ 
ing of orthoclase, acid plagioclase, and microcline in the order named. 
Feldspar phenocrysts, 3 mm. in length, are scattered through the rock, and 
in their border portions are intergrown with quartz. Small grains of 
magnetite and of ilmenite partly altered to leucoxene are present. There 
is only a little mica—biotite and seric-ite—in the rock, but chlorite probably 
derived from biotite is common. Garnets, light pink in color, are of 
frequent occurrence; they usually contain numerous inclusions of quartz, 
and in places show micrographic intergrowths. Small zircons are plentiful 
as inclusions in the larger crystals of quartz. 

About 100 yards north of the rock just described there are outcrops 
of hornblende schist, and the rock with which it is in contact is inter¬ 
mediate in mineral composition between the typical granite of the Gold 
Hill area and the hornblende schist. 

A specimen (83) of this rock is white to light gray in color, fine¬ 
grained, and contains small prisms of dark green hornblende in a white 
ground-mass. There may also be distinguished a few small phenocrysts 
of feldspar, quartz, a little pyrite, small grains of magnetite, and occa¬ 
sional pink garnets. Under the microscope, the feldspar phenocrysts, 
ranging up to 2 mm. in length, are seen to be acid plagioclase; they are 
very irregular in outline, are often broken, and have a corroded appear¬ 
ance. The ground-mass, consisting chiefly of quartz and feldspar, fre¬ 
quently shows micrographic intergrowths. The hornblende shows idio- 
morphic outlines, is dark-colored, and strongly pleochroic. A little chlorite 
is present, probably as an alteration product of the hornblende. Ilmenite 
partly altered to leucoxene and minute inclusions of zircon make up the 
remaining accessories. 

About half a mile south of Big Byrd Creek and iy 2 miles southeast 
of Kent’s Store there are outcrops of chlorite schist in the road. The 


80 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

schist (Specs. 80, 81, and 160) is clearly derived from a hornblende¬ 
bearing rock, and under the microscope fragments of unaltered hornblende 
can be identified. The rock which has undergone the least alteration shows 
the least schistosity. Small grains of pink rutile are scattered through 
the rock and can be easily recognized with the naked eye. 

Examined microscopically the rock is seen to consist largely of chlorite 
and needles of secondary hornblende. Unstriated plagioclase feldspar, 
quartz, and unaltered fragments of primary hornblende are also present, 
together with numerous small grains of rutile and titanite, and a few 
inclusions of zircon. The titanite is partly if not entirely secondary after 
rutile and some of the larger masses contain nuclei of the unaltered 
mineral. 

Hughes farm .—On the Hughes farm, half a mile northwest of the 
Tellurium mine, numerous pieces of breccia are found on the surface. 
The rock (Spec. 207) consists of angular and subangular fragments of 
quartz, feldspar, and fine-grained garnets, which have been more or less 
silicified and recemented by silica. Small cavities, lined with quartz 
crystals are occasionally present, and the secondary silica contains a little 
pyrite. The texture of much of the cementing silica, when it is examined 
megascopically, suggests that it was originally deposited as calcedony and 
subsequently altered to quartz. The fragments of country rock are largely 
replaced by silica. 

The distribution of this rock in a northwest and southeast line, a 
quarter of a mile or more in length, suggests that the breccia was formed 
by faulting, and that the cementing silica was deposited by solutions 
circulating along the fracture. 

Rosney Granite Area. 

There is a considerable area of granite in the vicinity of Rosney, the 
terminus of the Buckingham Branch of the Chesapeake and Ohio Railway, 
but because of the lack of outcrops it is not possible to determine its 
precise extent. On the west it is in contact with quartz-sericite schists 
and on the east similar schists intervene between the Rosney area and the 
granite of the Columbia area. It is not improbable, however, that the two 
areas are connected beneath the sediments of the Farmville Triassic area, 
which lies a short distance to the southeast. 

The granite is fine-grained, very schistose, and varies in color from 
light to dark gray. A specimen (383) from an outcrop in the road about 
three-quarters of a mile northwest of Rosney, contains both biotite and 
hornblende, the two minerals being distinguishable from each other with 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


81 


difficulty in the hand specimen. In a thin section, which was examined 
under the microscope, the feldspar was all plagioclase (oligoclase), and 
no potash feldspar could be identified. Twinning after the albite law is 
abundant and occasionally a little twinning after the pericline law may 
be seen. The hornblende is dark green in color and frequently shows 
idiomorphic boundaries; the biotite varies from brown to green and is 
strongly pleochroic. Both minerals show alteration to epidote, but no 
chlorite was identified. Many of the quartz and feldspar individuals are 
fractured and show optical distortion. Ilmenite, largely altered to leu- 
coxene and limonite, and idiomorphic crystals of zircon make up the minor 
accessories. 

Between the rock just described and the contact, about half a mile 
northwest, there are no outcrops, but the residual decay indicates the 
presence of several bands of hornblende schist. In the road half a mile 
southwest of Bosnev a fine-grained hornblende schist is exposed. It is a 
dark gray, even-granular rock composed for the most part of feldspar, 
hornblende, quartz, and a little biotite, with occasional small pink garnets. 

On the north side of Whispering Creek, 2 miles south of Bosnev, several 
pieces of porphyry were found, which probably belong to a dike, as the 
country rock in this vicinity is chiefly quartz-sericite schist. The rock is 
only slightly schistose and is therefore probably of later origin than the 
granite near Bosney, but it is not improbable that there is some genetic 
relation between the two occurrences. 

The rock (Spec. 388) contains numerous light gray, rounded pheno- 
crysts of feldspar, 5 to 6 mm. in diameter, which are surrounded by a 
ground-mass of fine-grained hornblende, feldspar, and quartz. Multiple 
twinning can be distinguished in places with a pocket lens, but most of 
the feldspars have a rough fracture because of the presence of microscopic 
inclusions. On weathering the rock gives a deeply pitted surface due to 
the early decomposition and removal of the feldspar phenocrysts. 

Under the microscope the large feldspars are seen to be micropoikilitic 
in texture, being full of inclusions of quartz and hornblende that range in 
size up to 0.2 mm. in diameter; they have indefinite boundaries that grade 
into the surrounding ground-mass; and the extinction angles and index 
of refraction indicate a composition near labradorite. The hornblende is 
light green to nearly colorless and contains occasional inclusions of quartz. 
The quartz grains contain numerous fluid inclusions, and irregular 
rounded grains of titanite are plentiful, some of them containing nucleal 
fragments of light yellowish rutile. 


82 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

About a mile west of Rosney and not far from the contact, there is a 
large amount of tourmaline present on the surface. Most of it occurs in 
long black prisms imbedded in vein quartz, but large masses were seen 
that consisted almost exclusively of small interlaced needles of tourmaline. 

Granite at Greeley Mine. 

Granite occurs in one of the openings of the Greeley mine, but there 
are no surface exposures and the occurrence is probably limited in its 
areal extent. The rock is described in detail on pages 206-207. The appear¬ 
ance of the rock, and the presence of much calcite and coarsely crystalline 
muscovite, suggests that extensively pneumatolitic action accompanied or 
followed the intrusion of the granite. 

Porphyries. 

DISTRIBUTION AND GENERAL DESCRIPTION. 

In the district lying between the Gold Hill granite area and the Wilm¬ 
ington embayment of the Columbia area, there are a number of outcrops 
of feldspar porphyry. Lack of sufficient exposures makes it impossible to 
determine the size and character of these bodies, but most of them are 
limited in extent and should probably be classified as dikes. The other 
rocks occurring in this district are chiefly chlorite schists, hornblende 
schists, quartz-sericite schists, and quartzites, all of which are intensely 
metamorphosed. 

The porphyries contain phenocrysts of feldspar ranging up to 2 mm. in 
length, and occasionally small eyes of quartz embedded in a fine-grained 
ground-mass composed essentially of feldspar, quartz, and usually a little 
hornblende, which may be more or less altered to chlorite and epidote. 
They vary considerably in composition, particularly in the amount of 
ferromagnesian mineral present. The phenocrysts are frequently fractured 
and the fragments separated, indicating that important differential move¬ 
ments took place during the crystallization of the rock. 

The composition of the porphyries, their texture, and their distribution 
relative to the larger granite areas, are all indicative of their close genetic 
relationship to the granite and point toward an approximate contempora¬ 
neity of origin. Some of them are closely similar to the granite in the 
Gold Hill area. 

DETAILS OF OCCURRENCES. 

In the road 1^2 miles northeast of Wilmington there is an outcrop of 
porphyry. It is a light greenish-gray rock (Spec. 63), fine-grained, and 


DESCRIPTIVE GEOLOGY AMD PETROGRAPHY. 


83 


slightly schistose. A few phenocrvsts of feldspar, 1 mm. in length, and 
small flakes of light green chlorite are the only minerals distinguishable 
megascopieally. 

Under the microscope the phenocrysts are seen to be well-formed 
crystals of acid plagioclase, nearly 1 mm. in length, which show twinning 
after the Carlsbad and albite laws. They are occasionally broken and the 
fragments separated by minerals of later crystallization. The ground- 
mass is fine-grained, even-granular, and consists of feldspar, quartz, 
chlorite, small needles of hornblende, a few flakes of biotite, calcite, 
epidote, and small inclusions of zircon, titanite, apatite, and rutile. 

Another outcrop occurs half a mile farther east where the rock (Spec. 
66) is essentially the same. The phenocrysts are slightly larger, ranging 
up to 1.5 mm. in length, there is a small amount of magnetite present, 
and alteration has been carried a little farther, so that epidote is more 
plentiful, occurring in granular aggregates with quartz and a little chlorite. 

On the southwest side of Big Byrd Creek, 21/2 miles southeast of 
Wilmington, there is an outcrop of schistose porphyry. The rock (Spec. 
68) is light gray with dark blotches due to areas of fine-grained biotite, 
and contains lenticular eyes of quartz, 4 mm. in length. A few feldspars, 
crystals of pyrite, red garnets, and a little fine-grained magnetite may 
also be distinguished in the hand specimen. 

Under the microscope phenocrysts of acid plagioclase, over 2 mm. in 
length, can be identified; and many of them are broken and split apart 
along cleavage planes, the fractures being filled with the minerals of the 
ground-mass. The lenticular eyes of clear, granular quartz contain fluid- 
filled cavities and numerous inclusions of idiomorphic zircon and rutile 
needles. The ground-mass is fine-grained and consists of feldspar, quartz, 
flakes of brown biotite partly altered to chlorite, and a little pyrite, 
magnetite, titanite, and zircon. 

In a branch on Mr. Williams’ farm, l 1 /^ miles northeast of Rivanna 
Mills, a rock (Spec. 54) is exposed which is light gray, fine-grained and 
only slightly schistose. Small pink garnets, pyrite, flakes of light green 
chlorite, and a little fine magnetite may be recognized with the naked 
eye. Examined microscopically the feldspar phenocrysts are seen to be 
smaller than in the rocks previously described, and they are much corroded; 
the ground-mass is coarser grained, but otherwise the same. The surround¬ 
ing rock is probably granite, but there are no exposures in the immediate 
vicinity. 

At the road corner, 2 y 2 miles south of Kent’s Store, there is an out¬ 
crop of fine-grained, bluish-gray rock (Spec. 128) containing small eyes 


84 


GEOLOGY OF THE GOLD BELT IN THE JAMES BIVER BASIN. 


of quartz 0.5 to 2 mm. in diameter. Under the microscope no feldspar 
phenocrysts could be identified; the quartz eyes contain rutile needles 
and well-formed zircons; and the ground-mass is composed essentially 
of feldspar, quartz, much hornblende in slender green prisms, and a large 
amount of fine-grained magnetite. A little zircon, titanite, and apatite 
are present as minor accessories. A similar rock found 50 yards east con¬ 
tains no eyes of quartz. 

A rock (Spec. 62), having a ground-mass similar to the one just 
described, was obtained from a well near the road 3 miles northeast of 
Stage Junction. Instead of having eyes of quartz there are a few imperfect 
phenocrysts of feldspar less than 0.5 mm. in length. 

A quartz porphyry, differing in texture and mineral composition from 
the rocks described above, occurs at the Morton mine, half a mile west of 
Johnson, Buckingham County. A microscopic description is given on 
pages 197-198. 

CAMBRIAN OR POST-CAMBRIAN. 

Diorite Dikes. 

DISTRIBUTION AND GENERAL CHARACTER. 

Dikes of altered diorite occur at several places in the area mapped, but 
there are a few good exposures, and the rock is of little importance as an 
areal formation. All occurrences that were observed are practically 
identical in appearance and mineral composition. The rocks were origi¬ 
nally composed essentially of hornblende and plagioclase feldspar, but the 
latter mineral is now almost completely altered to a fine-grained aggre¬ 
gate of zoisite, epidote, and other secondary products. 


AGE. 

Since these rocks show little or no evidence of dynamic metamorphism, 
they must be younger than the pre-Cambrian rocks into which they have 
been intruded; and the fact that some of them are very slightly schistose 
indicates that they solidified before the close of the crustal movements 
which deformed the Ordovician rocks. For these reasons the diorite dikes 
are believed to be Cambrian or possibly Ordovician in age, but they may 
be younger. 

DETAILS OF OCCURRENCES. 

Palmyra .—A dike of partly decomposed diorite outcrops in the road 
near the northwest corner of the Courthouse yard at Palmyra, but the 
size of the dike could not be determined. The rock is composed essentially 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


85 


of partly altered feldspar and dark green hornblende, and shows marked 
sc-histosity in the hand specimen. Under the microscope the feldspars are 
seen to be almost entirely altered to saussnritic aggregates of epidote, 
zoisite, and other secondary minerals, bnt in places a few residual frag¬ 
ments of basic plagioclase can be identified. The hornblendes are ragged 
in outline and show partial alteration to chlorite. 

Long Island Creel '.—The county road from Palmyra to Wilmington 
crosses a dike of weathered diorite about 100 yards east of Long Island 
Creek. The dike appears to be 100 yards or more in width, but could not 
be traced for any distance because of the lack of exposures. The strike is 
probably northeast and southwest. The rock is similar in appearance and 
composition to that described above, excepting that the percentage of 
hornblende present is slightly greater and the sc-histosity is scarcely 
noticeable. 

Benton mine .—Pieces of weathered diorite were found on a rock pile 
in the vicinity of the shaft at the Benton mine. The rock (Spec. 221) is 
massive, even-granular, and shows no evidence of schistosity. It consists 
of green hornblende in crystals 1 to 2 mm. in diameter, which are uni¬ 
formly distributed through a fine-grained, white ground-mass resulting 
from the alteration of feldspar. Under the microscope the feldspars are 
seen to be almost completely altered to secondary minerals, chiefly zoisite 
and epidote. The hornblende shows partial alteration to chlorite, and a 
little quartz, probably secondary, may also be distinguished. 

Bowles mine .—On the Bowles tract, about l 1 /^ miles west of Tabscott, 
pieces of diorite float were found on the surface, but no outcrops could be 
discovered in place. The rock is similar in every way to that which occurs 
at the Benton mine. 

TRIASSIC. 

Diabase Dikes. 

DISTRIBUTION AND GENERAL CHARACTER. 

Diabase dikes, or trap rock as they are commonly called, are of occa¬ 
sional occurrence in all portions of the area mapped. They are in no wise 
different from the other dikes belonging to the same great series, which 
are found intersecting the older rocks all along the Atlantic slope from 
Xova Scotia to Alabama. These dikes are especially abundant in some 
of the Triassic areas, and cut all formations excepting the Cretaceous and 
later sediments of the Coastal Plain. 

In the area covered by the present report the diabase dikes vary in width 
from a few inches to 200 or 300 feet, and at least one of them can be traced 


4 


86 GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIX. 

for a distance of over a mile, its course being marked by occasional out¬ 
crops, and the black weather-beaten bowlders, which are locally called 
■“nigger-heads.” The dikes are usually approximately parallel to the 
strike of the enclosing rocks, and are nearly vertical. 

The diabases are dark brown to black in color, and vary from medium 
fine-grained to aphanitic in texture. They are composed essentially of 
lime-soda feldspar, augite, and magnetite, while olivine is present in some 
and absent in others. These rocks are exceedingly hard and tough, and 
on account of this fact together with their good cementing qualities, they 
make excellent material for macadamizing roads. 

DETAILS OF OCCURREXCES. 

Columbia .—One of the largest and most persistent dikes in the district 
is exposed in the county road, a mile northeast of Columbia, where it is 
possibly 100 yards wide. It has a strike of approximately X. 15° E., and 
can be traced in a southwest direction as far as the river. The large out¬ 
crop of diabase half a mile east of Stage Junction lies in the same line 
of strike and may be a continuation of this dike, but lack of exposures 
makes it impossible to trace it on the surface. 

The rock (Spec. 46) is dark brown, and rather coarse-grained, showing 
a marked ophitic texture even in the hand specimen. The feldspars 
range up to 8 mm. in length, and show polysynthetic twinning to the 
naked eye. Examined under the microscope the rock is seen to be com¬ 
posed of plagioclase, augite, magnetite, pyrite, and occasional flakes of 
biotite. The augite is mostly colorless in thin sections, but in places is 
finely twinned with a light green variety. Magnetite and pyrite are both 
plentiful in small irregular grains The biotite is dark brown, strongly 
pleochroic, and shows partial alteration to chlorite. Xo olivine was 
identified. 

Grannison mine .—A dike of olivine diabase outcrops near the old mill 
at the Grannison mine, three-quarters of a mile south-southwest of Pryors 
Crossroads. It has a strike of approximately X. 25° IV., but the width 
and length could not be determined. The rock is coarse-grained and the 
ophitic texture easily distinguishable to the naked eye. Examined under 
the microscope (Spec. 97) it is seen to consist of lime-soda feldspars, 
augite, much olivine, a few grains of magnetite, less pyrite, and a little 
carbonate (probably calcite). The feldspars occasionally show pericline 
as well as albite twinning, and zonal extinction is common. The carbonate 
is probably derived from the alteration of feldspars. 


DESCRIPTIVE GEOLOGY AND PETROGRAPHY. 


87 


Pemberton .—A mile west of Pemberton, a diabase dike is exposed on 
either side of the narrow neck of land formed by the sharp bend in the 
river. Where well exposed the dike is only 5 or 6 feet wide, and while 
approximately vertical is very irregular in its dip. The strike is nearly 
north and south. The rock (Spec. 24) is medium-grained, even-granular, 
and dark gray in color. Under the microscope it shows the typical ophitic 
texture, and is composed of plagioclase, augite, and small idiomorphic 
grains of magnetite partly altered to limonite. The rock cut by the dike 
is a fine-grained, light gray granite-gneiss. 

Dillwyn .—A dike of olivine diabase outcrops in the town of Dillwyn 
(see map, p. 185), and a similar dike, which is described on page 187, is 
found near the London and Virginia mine, three-quarters of a mile north 
of Dillwyn. The rock is dark brown in color, medium coarse-grained, and 
is composed of plagioclase, augite, olivine, and magnetite. The olivine 
shows extensive alteration to sepentine. 

Other localities .—Several dikes of weathered diabase are exposed in 
the bluffs on the south side of James River near New Canton, and similar 
dikes were observed cutting the Ordovician slates. Diabase dikes at the 
Bondurant and McKenna mines are described on pages 195 and 254, re¬ 
spectively. Other occurrences are too numerous to mention in detail, and 
none of them differs in any material way from those already described. 


CHAPTER III. 


PHYSIOGRAPHY. 

INTRODUCTION. 

Virginia is naturally divided into three major provinces: (1) the flat- 
lying Coastal Plain which extends from the continental shelf, now 30 to 
50 miles east of the present shore-line, to the fall-line at the head of 
tidewater; (2) the Piedmont Plateau extending from the Coastal Plain 
on the east to the foot of the Blue Ridge; and (3) the Appalachian 
Mountains province which embraces the western or mountain portions 
of the State. (See fig. 1.) 

The Piedmont Plateau lying between the Coastal Plain and the Appa¬ 
lachian Mountains has a width of about 40 miles in the northern portion 
along Potomac River, but going south it widens until at the Virginia- 
Carolina state-line it extends for nearly 175 miles. The district under 
consideration is located in the center of the Piedmont Plateau province 
where the width is about 75 miles. The district presents the general 
surface features characteristic of the Piedmont Plateau throughout Vir¬ 
ginia; low relief, a network of streams which afford perfect drainage to 
the region but which are heavily loaded with sediment, and a deep mantle 
•of residual decay which covers most of the country except where the larger 
streams have cut down their valleys into the underlying rock. 

RELIEF. 

The elevations indicated on the map of the area (see PI. I, in pocket 
at back of book), by means of contour lines, are approximately correct, 
and serve to portray the principal physiographic features. The topography, 
as shown on this map, is adopted from the topographic sheets of the United 
States Geological Survey, with corrections by the writer. 

The most characteristic feature of the relief is the absence, over the 
entire area, of any notable elevations, with the single exception of Willis 
Mountain. This fact is forcibly impressed on the observer by the bird’s-eye 
view of the country obtained from the top of Willis Mountain. Looking 
from this elevation, the country appears as a broad, flat plain, stretching 
from the foot of the mountain toward the north, east, and south as far as 
the eye can reach, while toward the west it is limited only by the foothills 
of the Blue Ridge. 


PHYSIOGRAPHY. 


80 


In traveling any great distance across country, one soon finds that the 
surface instead of being perfectly level, is gently rolling, and consists, for 
the most part, of broad, flat-topped ridges and comparatively narrow 
valleys. If, however, one follows one of the main ridge roads, which have 
from the earliest days been the chief transportation routes of the country, 
the illusion of a vast level plain is maintained, for many of the ridges 
extend along distances with little variation in altitude. Thus, in travel¬ 
ing over the roads that lead from Cartersville to Cumberland, New Canton 
to Dillwyn and Buckingham, or from Stage Junction north by way of 
Wilmington, one may go for distances of 15 or 20 miles over an apparently 
level country. 

Glancing at the map, it is seen that neighboring ridges have approxi¬ 
mately the same elevations, but that in passing across the area from east 
to west the height of the elevations gradually increases; along the eastern 
border of the area the ridges are about 450 feet above sea level, while in 
the western portion they average from 550 to 600 feet in elevation. If it 
were possible to fill in all of the valleys level with the tops of the ridges, 
we would have a broad, flat plain sloping gently toward the ocean, and it 
is believed that this was the condition of the land surface at a former 
period, before the streams had cut their channels down to their present 
levels. 

The rivers and larger creeks have cut their valleys deepest, about 250 
feet below the present surface of the old peneplain, the smaller creeks 
somewhat less deeply, and their tributary branches only from 50 to 150 
feet. All of the larger streams flow through narrow trench-like valleys 
with very limited bottom lands. In places where the rocks are especially 
resistant, as is the case with the quartzite beds at Bremo Bluff, the river 
lowlands are practically absent and the stream is bordered by almost 
vertical cliffs. (See PI. Ill, and fig. 2.) 

Willis Mountain, in the southwestern corner of the area, projects abruptly 
from the average level of the Piedmont Plateau and rises to a height of 1,159 
feet above sea level. It is a prominent feature of the landscape for miles 
around, and is the most noticeable elevation found in the State, east of 
the outlying ranges of the Blue Bidge. (See figs. 4 and 5.) Topo¬ 
graphically, it is a narrow ridge extending about two miles in a north 
and south direction, and the crest of the ridge is formed by a narrow 
wall of rocks, perhaps 100 feet high, which is so nearly vertical that it 
can be scaled only in places and with difficulty. (See PI. IV, fig. 1, and 
PI. VI, fig. 2.) The dip of the strata is slightly toward the west, and the 


90 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


large fragments which have fallen along the eastern base have rendered 
this the easiest direction of ascent. From the foot of this wall-like 
precipice the mountain slopes steeply down to its base. The rocky ridge 



Fig. 4.—North end of Willis Mountain from the west. 



Fig. 5.—South end of Willis Mountain from the west. 

forming the crest of the mountain is notched in several places, so that a 
number of distinct summits occur. The deepest of these notches is near 
the south end of the mountain, and the southern knob which it separates 
from the main ridge is locally known as Round Mountain. Willis 

















PHYSIOGRAPHY. 


91 


Mountain owes its origin to the resistant nature of the cyanite schist which 
outcrops along its crest, and which has offered greater resistance to erosion 
than any other rock in the region. 

DRAINAGE. 

The great master-stream of the area, James River, flows in a general 
southeasterly direction and cuts directly across the strike of the upturned 
edges of the rock strata, maintaining its course without reference to varia¬ 
tions in their hardness. With its headwaters rising among the ridges of 
the Alleghany Mountains, James River flows eastward, cutting its way 
through the Blue Ridge as well as all minor barriers that rise athwart its 
course, and finally empties into the Atlantic Ocean. This independence 
of the chief structural features of the country, together with its intrenched 
meandering curves, proves that the river developed its course on a broad, 
level plain, before the present ridges were formed. Such a river is called 
an antecedent stream. 

The principal streams draining the area and entering James River 
from the north are Rivanna River and Byrd Creek (see map, PI. I). Both 
of these flow southeasterly across the strike of the upturned rock strata 
and show deeply trenched winding valleys, indicating that they are also 
antecedent streams. 

Slate and Willis rivers are the largest streams that cross the area and 
enter the James from the south. It should be noticed that both rivers, 
after flowing in a general northeasterly direction throughout most of their 
length, suddenly change their courses as they approach the James, and 
enter it from an easterly or even a northeasterly direction; and, moreover,' 
their lower courses are extremely crooked, while their upper valleys are 
fairly straight. These two rivers were doubtless at one time superimposed 
streams similar to those on the other side of James River, but as their 
direction of flow was nearly parallel to the strike of the rock strata, their 
courses were more easily modified and adjusted to the rock structure. 
This possibly explains the peculiarities in the courses of these streams 
and also the fact that their valleys are slightly broader and less steep than 
those of the corresponding streams on the opposite side of James River. 
Slate and Willis rivers may be considered as antecedent streams that have 
subsequently undergone modification and are now in partial adjustment 
to the structure. 

Appomattox River, which crosses the southeast corner of the area, is 
clearly another antecedent stream similar to James River into which it 
flows some distance beyond the borders of the map. 


9 2 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


It is thus seen that all the larger streams of the area are either 
antecedent streams or streams that are only in partial adjustment to the 
structure, and that they all show a strong tendency to flow in a south¬ 
easterly or easterly direction. 

Most of the creeks and many of their branches are streams that owe 
their location to the underlying rock formations. These streams flow 
northeasterly or southwesterly parallel to the structure of the country, 
their direction of flow being controlled by their proximity to some larger 
antecedent stream. Hunt Creek, Phelps Creek, and Little Byrd Creek 
may be mentioned as good examples of structural control of drainage. 

Hunt Creek has eroded its valley in the long, narrow area formed by 
the Arvonia slate belt, while the ridges on either side are composed of 
more resistant rocks—schistose quartzites and conglomerates. 

Phelps Creek runs in a northeasterly direction through an area of 
highly metamorphosed schists and enters James River just east of Xew 
Canton. The ridge on the west side of the valley is composed of quartzite, 
while on the east stretches the granite area. A complementary creek flows 
southwest and enters James River directly opposite. 

Little Byrd Creek flows southwest within the area of pegmatite, which 
is less resistant than the granite and hornblende schists on either side. 

The hundreds of small tributary branches that drain into the larger 
streams flow in every conceivable direction, their courses being controlled 
partly by the geological structure, but chiefly by their proximity to one 
of the larger streams. 

Most of the streams draining this area are rather swift and flow over 
occasional rapids, due to outcropping ledges of harder rock ; their waters 
are usually muddy because of the large amount of fine material carried 
in suspension which has been derived from the residual soils that almost 
everywhere cover the underlying rocks. 

It is interesting to note that in the case of some of the larger streams 
that are in structural adjustment, such as Little Byrd Creek on the north 
side of James River and Muddy Creek on the south, the principal tributary 
branches all enter from the west. This phenomenon is due to the eastern 
slope of the peneplain in which the streams have eroded their valleys. 

The movement resulting in the tilting of this plain did not take place 
all at once, but undoubtedly extended over a long period of time, and was 
probably interrupted by periods of quiescence. Every increase in the 
eastern tilt of the land surface resulted in an increased velocity of the 
streams flowing in an easterly direction with a corresponding increase in 


PHYSIOGRAPHY. 


93 


their powers of erosion. Streams flowing westward had their velocities 
diminished and if the amount of movement was sufficient the direction of 
flow may even have been reversed in some cases. The net result of this 
tilting was to cause the streams flowing in an easterly course to cut back¬ 
ward and lengthen their valleys faster than the streams flowing in the 
opposite direction. This process may have been accompanied by an 
easterly migration of the parent stream since the tilting would tend to 
induce greater erosion along the eastern bank. The bluff's appear to be 
somewhat more prominent on the east sides of these streams than on the 
west, but the difference is certainly not great. The chief result of any 
easterly displacement of the parent stream would be to lengthen the courses 
of its tributaries from the west and shorten those from the east, but it is 
not believed that this was an important factor in producing the unsym- 
metrical streams described above. 

The rapid headward erosion of easterly flowing streams, caused by the 
tilting of the peneplain would bring about a condition favorable to stream 
capture; that is to say, the stream with greater velocity might cut its way 
back to some neighboring stream and divert the upper portion of its drain¬ 
age. A close study of the region lying west of Little Byrd Creek indicates 
that this may have taken place, and that the headwaters of some of the 
branches north of Lantana, which now flow east into Little Byrd Creek, 
at one time drained southward into the large branch which enters Little 
Byrd Creek a mile above its mouth. 

The principal facts in favor of this theory are as follows: 

(1) The large branch which heads just east of Lantana and flows 
south into Little Byrd Creek has a valley that is almost as broad as that of 
Little Byrd Creek itself. 

(2) The divide near the headwaters of this branch is low and in 
places swampy. 

(3) Several of the tributary branches draining the area northeast 
of Lantana have a sharp bend in their courses which is approximately in 
alignment with the prolongation of the valley running south from Lantana. 

(4) On some of the low ridges northeast of Lantana residual patches 
of placer gravel were formerly worked for gold. The position of this gravel 
is high aboVe any of the neighboring streams, and these remnants are all 
that is left to indicate the location of an old stream bed which has long 
since been almost entirely removed by erosion. 

PHYSIOGRAPHIC HISTORY. 

It is known that this region passed through a long and varied history 
before the present physiographic features began to take form; it underwent 


94 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

many changes in elevation, and for long periods of time it was depressed 
below sea level while the great series of sedimentary beds was being 
deposited. Later these beds were consolidated into hard rock and subjected 
to compressive forces which produced the complicated system of folding 
and faulting that is so noticeable wherever the rocks are well exposed. 
This process was accompanied and followed by intrusions of igneous rocks, 
and the area was elevated high above sea level. 

As soon as the land appeared above water, the agents of the atmosphere 
began their work of decomposition and disintegration, and the newly 
formed streams began to wear away the land surface and transport the 
products of weathering to the ocean, where the material was redeposited 
to form new beds of sediments. Denudation was continued until the region 
was beveled across hard and soft formations alike, and the country reduced 
to a condition bordering on base-level. Such a surface is known as a pene¬ 
plain. 

The area has undoubtedly experienced several periods of peneplaination 
followed by renewed elevation of the land surface, but it is unlikely that 
the Piedmont section as a whole has been depressed below sea level since 
Ordovician time. 

Following a period of base-leveling, the surface was warped enough 
to allow the Newark beds to be laid down in long, narrow trough-like 
basins, but, since that time, degradation has continued without inter¬ 
ruption. The earliest great peneplain of which evidence remains extended 
far beyond the limits of this small area, and has been called the Kittatinny 
peneplain.® It probably dates from the Cretaceous period. 

In many places in the Appalachian States peneplains of later date 
than the Kittatinny plain have been noted, and while it is possible that 
periods of subsequent base-leveling may have occurred in this section, they 
have not been identified, and it is improbable that more than one plain 
can be distinguished within the limits of this area. 

It is impossible to accurately determine the thickness of the material 
removed during the ages in which this degradation of the land surface 
was going on, but certainly it is to be measured in thousands of feet. All 
of the changes outlined above took place gradually and covered a long 
period of time. While we can not even approximately estimate the length 
of this time as measured in years, it must have been very great even in 
comparison with the time which has since elapsed. 

aWillis, Bailey, The Northern Appalachians, Physiography of the United 
States, p. 189. 



PHYSIOGRAPHY. 


95 


During the latter stages of peneplaination decomposition proceeded 
much faster than degradation; the products of rock decay accumulated 
more rapidly than they could he removed by the slow-moving streams, 
which had almost attained base-level, and a deep mantle of residual soil 
was gradually formed that completely covered the hard rocks below. 

The appearance of the surface at that time was probably not very 
different from that of the lower Mississippi valley to-day. The land was 
flat and featureless and elevated but little above sea level. Willis 
Mountain was probably the only elevation within the limits of this area 
that stood above the monotonous level of the plain. The stubborn resist¬ 
ance to weathering offered by the rocks forming this mountain served to 
protect it from the complete reduction that had befallen the surrounding 
area, and left it standing as a solitary monadnock. The rivers meandered 
sluggishly over the land in wide curves, and there were no marked divides. 
The course of these streams is not known, but many conditions indicate 
that they possibly drained toward the west. 

In this condition a very slight tilting of the land surface was sufficient 
to change the courses of the streams, or even cause them to flow in the 
opposite direction, and it was upon this surface that the new system of 
drainage represented by the present antecedent streams was inaugurated. 

The new streams, assuming their positions while the rocks of varying 
hardness were still covered by a deep blanket of residual decay and 
alluvium, were not influenced by the structure of the underlying forma¬ 
tions, and therefore ran slowly in winding curves closely coincident with 
those that they now possess. The establishment of the new drainage, 
however, was shortly followed by a progressive elevation of the land which 
quickened the streams, and they began the work of deepening their 
channels. 

After cutting through the soft overlying material and exposing the 
fresh rock below, the larger streams continued the work of corrading their 
channels in the more resistant formations. As fast as renewed elevation 
of the land surface raised the hard beds athwart their course, the streams, 
confined to their channels and restrained from altering their courses by 
the deep valleys which they had excavated in the softer material, were 
forced to cut through hard and soft strata alike. It was in this way that 
the larger streams were superimposed upon the structure of the undecom¬ 
posed underlying rocks. 

The fact that the rivers have not been able to cut their channels in 
hard rocks as rapidly as in the softer formations, accounts for the rapids 


96 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

that frequently occur. The rapids in James River at Bremo Bluff furnish 
a good example. Here the river flows across beds of hard quartzite 
which, dipping vertically, are interbedded with softer mica-garnet schists. 
Because of the greater resistance of the quartzite to erosive action, the 
river has not been able to cut its bed downward or to widen its channel 
in it as rapidly as in the softer rocks, and therefore the quartzite beds 
stand out as ledges from the bottom of the river and project from the 
sides of the valley in bold cliffs. (See fig. 2, and PI. III.) At the bridge 
the valley is only 500 yards wide from bluff to bluff and there are practi¬ 
cally no bottom lands, but at a distance of only one mile up or down the 
river, the valley is a mile or more in width, the river being bordered by 
broad, alluvial flats which at times of very high water may be completely 
flooded. 

While the larger streams were able to deepen their valleys, even in the 
hardest rock, and continued to flow across the strike of the strata, the 
secondary streams were not strong enough to maintain their courses in 
opposition to the forces tending to divert them into conformity with the 
structure. As a result, these streams were gradually diverted to the areas 
of softer rock, and this adjustment was more readily brought about as the 
original direction of flow was more nearly parallel to the rock structure. 

It was through this struggle between the eroding power of the streams 
and the slowly rising land surface that the existing surface configuration 
was developed. 

At present the larger rivers of this area are, in some places, cutting 
their channels deeper, while at others, as evidenced by the large islands 
and wide areas of bottom lands, they have begun to deposit part of their 
burden. The valleys are slowly being widened, chiefly through the de¬ 
composition and disintegration of the rocks under atmospheric agencies. 

The smaller streams have not yet cut down through the decomposed 
material to fresh rock, but the rate at which they are now cutting is 
probably in most cases greater than that of decomposition. 

Evidence of the former position of the rivers is furnished by deposits 
of water-worn gravel, representing the remains of old river terraces, that 
are found at various places high above the present level of the river. One 
of these old river terraces, some 200 feet above the present river bed, is 
located near Stearnes on the north side of James River, where it can be 
traced up stream for a distance of about a mile. 

A profile of James River shows a rather sharp change in the grade, 
where the river crosses from the sedimentary rocks to the granite, just 


PHYSIOGRAPHY. 


97 


below Bremo Bluff." From Lynchburg to this point, a distance of 80 
miles, the river falls an average of 3.71 feet per mile, while flowing 
over the granite from this point to Lorraine, 12 miles above Richmond, 
which is a distance of 91 miles, the river falls only .606 feet per mile. In 
both cases the grade is fairly uniform. The change is too sharp to be 
accounted for by the natural increase in the grade of the stream with its 
distance from the mouth, and is probably due to the difference in the 
character of the formations. Another possible explanation is that the tilt¬ 
ing of the peneplain lias not been uniform, but this would hardly account 
for the localization of the change in grade at this particular point. There 
is no evidence of faulting, and the rock exposures along the bluffs are 
particularly good in this vicinity, so that it would probably show if present. 

«See Plate VI, opposite p. 94, Hydrography of Virginia, Bull. No. Ill, Geol. 
Survey of Virginia, 1906. 



CHAPTER IV. 


STRUCTURE AND METAMORPHISM. 

INTRODUCTION. 

Previous descriptions have brought out the fact that the dominant 
rock formations occur in zones or belts extending in a northeast and 
southwest direction, and dipping at high angles, usually toward the east. 
Sedimentary rocks, from the manner of their formation, are necessarily 
laid down in nearly horizontal beds; but, in the region under considera¬ 
tion, the older rocks have been subjected to severe compressive stresses 
which have crumpled and squeezed the beds into close folds, mashing even 
the hardest rocks into schists and gneisses. The rocks have also been 
profoundly altered by the intrusion of large igneous masses. Subsequently 
erosion has gradually removed the overlying material, beveled off the edges 
of the upturned beds, and in places exposed the underlying igneous 
intrusives. 

The lack of accurate knowledge concerning the structural relations 
of the rocks in the surrounding territory, and the scarcity of exposures, 
due to the great depth of residual rock decay, make it impossible to work 
out many of the details of structure in the limited area considered in this 
report, but some of the more important features will be discussed below. 

STRUCTURAL FEATURES. 

Folding. 

There are three well-defined belts of pre-Cambrian metamorphic rocks 
of sedimentary origin, which consist essentially of knotted schists and 
interbedded quartzites. The most easterly of these belts extends southwest 
from Shannon Hill to Stage Junction; the middle belt is exposed in the 
river bluffs near Xew Canton and extends in a northeast and southwest 
direction approximately parallel to the first; the third belt is located 
along the northwestern margin of the map (PL I) between Palmyra and 
Strathmore. This areal distribution of the rocks is strongly suggestive 
of folding, and there are a number of facts which indicate that there is 
an anticlinal fold between the eastern and middle belts, and a synclinal 
fold between the middle and western belts. 

In the eastern belt the rocks dip southeast at an average angle of 45°, 
in the central belt they stand nearly vertical, and in the western belt they 



STRUCTURE AND METAMORPHISM. 


99 


dip at an angle of 75° to 80° southeast. The central and western belts are 
separated by the long narrow area of Ordovician sediments, which were 
deposited unconformably upon the eroded surface of the older pre- 
Cambrian rocks; the eastern belt is almost entirely cut off from the other 
rocks by the large areas of intrusive granite (see p. 102). 

The crustal movements continued with less intensity after the depo¬ 
sition of the Ordovician sediments, and these beds were compressed into 
the synclinal fold to which they owe their preservation. The Ordovician 
slates are extensively faulted and crumpled into innumerable minor folds, 
but the synclinal nature of the belt is shown by the presence of a basal 
conglomerate along the contact with the older rocks on both sides. The 
close folding and faulting shown in the section along the south side of 
James River (see PI. VII) indicates that the beds were probably of no 
great thickness, and that they could not have been folded under conditions 
of very deep burial. The lack of a well-developed slaty cleavage in slate 
from the bottom of the synclinal trough has been commented on in a 
previous chapter (see pp. 45-46). 

In the time that has elapsed since their deposition and subsequent 
folding, erosion has removed all of the Ordovician sediments except the 
long narrow belt of rocks, preserved in the bottom of the synclinal trough. 
Rivanna River has cut completely through this narrow remnant and ex¬ 
posed the underlying granite, thus proving the shallow character of the 
formation. In the railroad cut, half a mile south of Carysbrook, the Ordo¬ 
vician sediments are exposed resting on the eroded surface of granite (see 
PI. VI, fig. 1), and as the river is approached the beds gradually thin out 
until they completely disappear. The slates are again exposed along the 
upper portion of Long Island Creek between Palmyra and Wilmington; 
and the creek, which in both its upper and lower portions is in direct 
alignment with the strike of the rocks in the two areas, probably owes its 
position to the slate belt, now partly removed by erosion. 

The small detached slate area, paralleling the main belt a short distance 
north of Fork Union station, probably represents a minor fold which has 
been separated from the main belt by erosion; and minor folding offers 
the most plausible explanation for the widening of the slate belt in the 
section along the south side of James River. 

It is not unlikely that there are numerous subordinate folds superim¬ 
posed on the major folds of the pre-Cambrian rocks, but the nearly iso¬ 
clinal dip, together with the lack of exposures, makes it impossible to work 
out minor details of this character. The presence of these minor folds is 
occasionally indicated by discordance between the bedding and schistosity 
—shown in Spec. 342 from the Buckingham mine. 


100 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


Faulting. 

Small faults, usually of the thrust type, are plentiful in the Ordovician 
slates and may be seen at many points in the bluffs along James River; 
they have also been detected in the pre-Cambrian rocks, and it is probable 
that many are concealed by the steep monoclinal dip of the bedding and 
schistosity. All the faults observed are approximately parallel to the 
strike of the rocks and it is unlikely that many of them cut across the 
structure. No large faults were definitely located along the boundaries 
between different formations although it is not improbable that such faults 
exist in a few places. 

Some faulting has taken place in this region as recently as Triassic 
times, for a number of faults have been discovered in the Farmville area 
(see p. 47), as well as in the other Triassic areas of Virginia. The dis¬ 
placement along these recent faults, however, is comparatively small and 
they do not seem to have affected the structure of the country in any 
important way. The occurrence, during the past few years, of several 
feeble earthquake shocks in the vicinity of Arvonia is possibly due to 
adjustments that are taking place along some of these fractures. 

The determination of faults in the granites and related igneous rocks 
is a more difficult problem, but the presence of cemented breccia on the 
Hughes farm, 2 1 /) miles west of Tabscott, and on the Dickey farm, 2 
miles southeast of Cremona, indicates that fracturing with more or less 
faulting has taken place at these points. 

Jointing. 

Joints are very plentiful in all portions of the area mapped, and, while 
they run in every conceivable direction, they show a decided preference 
for certain quarters of the compass. Joints having a general northeast- 
southwest strike, approximately parallel to the schistosity, are most common 
and those with a northwest-southeast trend are second in importance. 
North-south and east-west strikes are comparatively rare. 

As a general rule joints are more closely spaced in the rocks of sedi¬ 
mentary origin than in the more nearly massive and compact rocks of 
igneous origin. For example, in the railroad cut half a mile south of 
Carysbrook, where Ordovician sedimentaries are exposed resting on the 
eroded surface of the older granite, the principal directions of jointing are 
N. 25° E., N. 60° W., and parallel to the contact which dips, southeast at 
an angle of less than 30°. In the granite the joints are spaced 2 to 4 
feet, while in the slate they are only 2 to 8 inches apart. 


STRUCTURE AXD METAMORPHISM. 


101 


Schistosity. 

Schistosity is that property of rocks which causes them to break most 
readily along certain parallel planes, and is due to mashing accompanied 
by more or less recrystallization of the mineral constituents. It is usually 
induced by the same compressive forces which result in folding and fault¬ 
ing, and is therefore parallel to the axes of the major folds. 

With certain exceptions, noted later, the strike of schistosity through¬ 
out the region mapped, is northeast-southwest at slightly varying angles, 
and the dip is usually steeply inclined toward the southeast. In the pre- 
Cambrian rocks of sedimentary origin the schistosity is almost always 
parallel to the strike and dip of the bedding; and the few exceptions to 
this rule which were noted are probably due to the presence of subordinate 
folds superimposed on the major folds. There are greater variations in 
the relation of schistosity to bedding in the Ordovician slates than in the 
older rocks, for these have not been subjected to such severe compression 
and the dip of the bedding is therefore less uniform. 

On the Stage Junction road, a mile north of Columbia, there are a 
number of rock exposures in the vicinity of the contact between the intru¬ 
sive granite and the older pre-Cambrian schists and quartzites. In these 
exposures the strike of the schistosity is approximately parallel to the 
contact, varying from X. 15° to 24° W., and dipping southwest at an angle 
of about 45°. This exception to the general trend of the schistosity affects 
both the sedimentary and the igneous rocks and is probably due to the 
intrusion of the latter. 

In most places the boundary of the granite area runs in a general 
northeast-southwest direction, approximately parallel to the strike of the 
bedding and schistosity of the neighboring sedimentary rocks; and in the 
few places where the contact cuts across the strike of the latter, the 
exposures are not sufficient to determine whether the anomaly described 
above holds true in other localities or not. 

A peculiar form of schistosity was observed in slate from the bottom 
of a synclinal fold (see pp. 45-46). Instead of the usual slaty cleavage it has 
a prismatic cleavage, which causes the rock to break with equal readiness 
in all directions parallel to the axis of folding, while it breaks with much 
greater difficulty at right angles to this axis. 

The schistose structure possessed by most of the granites and 
related igneous rocks of the district, was probably induced by pressure 
or mashing of the massive rock, but the gneissoid banding shown in certain 
localities (see PI. VIII, tig. 1) is evidently a primary flow structure. In 


102 


GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIX. 


the Elk Hill complex (see p. 57) granite occurs in the form of inumer- 
able dikes, varying from a few inches to 50 feet or more in width, 
which have been intruded into the hornblende schist; and while for the 
most part the granite follows the planes of schistosity in the older rock 
it occasionally cuts directly across. Some of the granite dikes have a much 
contorted gneissic banding; and since the contortions are not shared by 
the older schist, they can not be explained by pressure, and must be due 
to movements in the partly solidified granite. 

Structural Relations of the Granite. 

Granite is a rock which forms only under conditions of deep burial, 
and therefore a large amount of overlying material must have been removed 
by erosion in order to expose the present surface. There is nothing to 
indicate that the material removed was essentially different from the for¬ 
mations that remain in contact with the granite, and that certainly in 
places overlie it. From this it should not be inferred that these same 
sedimentary formations necessarily extended for an indefinite distance to¬ 
ward the east; but it is believed that they formerly covered the granite 
in the immediate vicinity of the contacts, and that they once covered the 
large areas, such as the one lying between Stage Junction and Fork Union, 
which are still partly or wholly surrounded. 

The areal distribution of the two formations indicates that the contact 
between the granite and the pre-Cambrian sedimentaries is not a uniform 
plane, but that the granite rises higher along certain lines that probably 
represent anticlinal folds. Such a line connects the granite embayment 
heading near Wilmington with the area lying between Kent’s Store and 
Tabscott, and there is evidence that the intervening region is underlaid 
with granite at no great depth. The sedimentary rocks in the region 
between these two granite areas are intensely metamorphosed, hornblende 
schists are common, and there are numerous intrusive bodies of porphyry 
and pegmatite. The latter, which are probably differentiates from the 
underlying granite, are limited to this particular region and do not occur 
in the schists on either side. Some of the facts indicating the presence of 
an anticlinal fold in this vicinity were given in a previous paragraph, and 
it is interesting to note that the gold veins are located chiefly in the limbs 
of these folds not far from the granite contact. 

In the southern portion of the area mapped the exposure of granite 
at the Greeley mine, a mile southwest of Gravel Hill, is in direct line of 
strike with the Eosney granite area; and the sedimentary rocks lying 


STRUCTURE AXD METAMORPHISM. 


103 


between these two localities show evidence of contact metamorphism. Some 
of the rocks, as at Tower Hill, are largely altered to garnet and sillimanite, 
and tourmaline-bearing quartz veins are plentiful. It is believed that 
granite closely approaches the surface along this northeast-southwest line, 
and that the few exposures which occur are located where erosion has 
removed the overlying cover of sedimentary rocks. It is probable that 
much of the pre-Cambrian sedimentary area is underlaid with granite at 
greater depths. 

Relations of the Hornblende Schists to the Granites. 

Hornblende schists are plentiful in the Columbia granite area and in 
the Elk Hill complex, but are rarely found elsewhere in the area of granitic 
rocks; their distribution and occurrence have been described in detail in 
a previous chapter. There are two hypotheses that may be offered in 
explanation of the presence of these schists: (1) They are due to the 

partial solution and recrystallization of inclusions of the country rock, and 
(2) they represent segregations from the original granite magma. Xo 
chemical analyses are available, but all of the field and petrographic 
evidence is in favor of the latter hypothesis. 

One of the chief objections to the first hypothesis is that, while the 
schists are more plentiful near the boundary of the granite area, there is 
no noticeable variation in their abundance or in their mineral composition 
consequent upon changes in the character of the sedimentary rocks along 
the contact. Moreover, they are abundant in the Elk Hill complex, which 
is situated far from the contact with sedimentary rocks. Another serious 
objection is the fact that the central portions of even the largest horn¬ 
blende areas show no evidence of a sedimentary origin. 

On the other hand, the areas of hornblende schists vary in abundance 
and size with the mineral composition of the granite; they are most 
plentiful in the southern portion of the Columbia area where ferromag- 
nesian minerals, especially hornblende, are abundant in the granite, and 
they are absent in the embayment between Wilmington and Carysbrook, 
where the ferromagnesian minerals are at a minimum. The reasons for 
believing that the granite near Carysbrook solidified later than the rock 
in other portions of the area were given on pages 62-63, and the field 
evidence is conclusive in showing that the hornblende schists crystallized 
prior to the complete solidification of the associated granite. 

The hornblende schists are remarkably uniform in mineral composi¬ 
tion, and the variations from the normal are all intermediate between the 


104 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


granite and the typical schist. Occurrences showing a gradation of granite 
into hornblende schist were described in detail in a previous chapter (see 
pp. 66-68). On approaching a large area of hornblende schist the potash 
feldspars and muscovite disappear from the granite and finally hornblende 
gradually takes the place of biotite. 

It seems probable that the hornblende schist and granite of the Elk 
Hill complex belong to the same period of intrusion as the rocks of the 
Columbia area, for they are similar in appearance and mineral composi¬ 
tion. Another fact, which lends support to this supposition, is the absence 
of hornblende schists along the contact between the Columbia area and 
the pegmatite belt, although the schists commonly constitute a border 
facies of the granite. This suggests that the Elk Hill complex may 
represent the real eastern border of the Columbia granite and that the 
intervening pegmatites may be residual differentiates from a common 
magma. 

As yet little is known of the processes by which rock magmas are 
differentiated into rocks differing widely in mineral and chemical com¬ 
position. In the absence of numerous chemical analyses of the rocks it is 
impossible to discuss the various theories of rock differentiation and their 
application to the present problem; but some of the more important facts 
concerning the differentiation of the hornblende schists will be summarized, 
and the probable processes will be briefly outlined. 

The hornblende schists crystallized prior to the granites with which 
they are associated, and they are more plentiful where the granite is 
hornblende-bearing. In the Columbia area the hornblendic granites 
probably solidified prior to the granites containing little or no hornblende. 
’Where hornblende occurs in the granites it is one of the minerals of early 
crystallization. The bodies of schist vary in size from small schlieren 
up to areas that are over a square mile in extent, and they are most 
abundant in the marginal portions of the granite area. 

The hypothesis outlined below, while only tentative in its nature, is 
based on the facts given in the previous descriptions, and serves to explain 
the observed relations between the hornblende schists and the associated 
granite. As the original magma gradually cooled, crystallization began 
in the border portions where the temperature was lowest, the more basic 
minerals separated out first; and in this way the marginal areas of horn¬ 
blende rock were formed. Differential movements, occurring after the 
basic border facies of the magma had partly or wholly crystallized, resulted 
locally in the intrusion of the still-fluid portions of the magma into the 


STRUCTURE AND METAMORFHiSM. 


105 


solidified rock, and caused the interleaving of the two rock types that is 
such a prominent feature of the Elk Hill complex. The detached areas of 
hornblende schist found within the central portion of the granite may 
represent material derived from the border portions, or possibly they are 
due to segregations in situ. 

The differential movements mentioned above may have brought por¬ 
tions of the solidified rock into contact with magma having a higher 
temperature and resulted in some resolution. This possibly explains the 
occurrence of intermediate rock types with unusual coarse textures, for 
when recrystallization followed upon partial solution any undissolved 
crystals would prevent supersaturation, which is commonly the cause of 
rapid crystallization and fine texture. 

It is believed that the granite near Carysbrook, which is low in ferro- 
magnesian minerals and contains no marginal areas of hornblende schist, 
was intruded in a partly crystallized condition (see pp. 62-63), and was 
the final portion of the magma to solidify. 

METAMORPHIC FEATURES. 

Regional Metamorphism. 

All the older rocks in the area studied, both those that are sedimentary 
and those that are igneous in origin, have been deeply buried in the 
anamorphic zone, and most of them show pronounced effects of dynamic 
metamorphism. Megascopic-ally these effects are manifested chiefly by 
the development of a schistose structure, which in some instances is accom¬ 
panied by gneissoid banding. In a rough way the degree of alteration is 
proportional to the age of the rocks; the pre-Cambrian sediments are the 
most schistose, the Ordovician rocks show less effects, and the Triassic 
rocks are practically unaltered. The degree of schistosity is also dependent 
on the composition and original texture of the rock. The pre-Cambrian 
quartzites, for example, are almost massive, while the fine-grained schists 
with which they are interbedded have a highly developed cleavage and 
almost perfect parallel orientation of the mineral constituents. 

Microscopically, the chief evidence of dynamic metamorphism is fur¬ 
nished by the fracturing, granulation, and optical distortion of certain 
minerals, by recrystallization, and by the complete or partial alteration of 
primary to secondary minerals, such as sericite and chlorite. 

The development of the pseudophenocrysts that occur in the knotted 
schists took place under mass-static conditions, for these minerals are of 
later formation and show no regular orientation relative to the schistosity 
of the rock. 


106 GEUUOGY O* THE GOLD BELT IN THE JAMES RIVER BASIN. 

Since the metamorphism of the different rock types has already been 
considered in the chapter on descriptive geology and petrography, a detailed 
discussion will not be given here. While the alterations outlined above 
have been attributed chiefly to mass-mechanical action under conditions 
of deep burial, it is probable that the changes have been greatly aided by 
the intrusion of the vast masses of igneous rock, only part of which have 
been exposed by erosion. 

Contact Metamorphism. 

INTRODUCTION. 

Under contact metamorphism, those changes will be discussed which 
are set in action b} r intrusive masses of molten rock. The metamorphism 
of the wall rock is manifested by recrystallization, usually with the pro¬ 
duction of new and characteristic minerals, and by changes in texture; 
the effects are at a maximum near the intrusive and decrease in intensity 
with the distance from the contact. The intrusive likewise shows more or 
less variation in texture and mineral composition as the contact is 
approached. 

It is now generally believed that the changes which take place in the 
vicinity of igneous intrusives are due chiefly to the action of highly heated 
water and other mineralizers set free by the solidifying magma. These 
highly heated vapors or gases, probably carrying a certain amount of 
silicates and other substances in solution, penetrate the surrounding rock 
through minute fractures and pores, bring about the formation of new 
minerals, and deposit their dissolved material. Acid magmas, such as 
those from which granites crystallize, are supposed to be richly provided 
with these mineralizers, and therefore commonly produce greater effects 
than more basic magmas. 

All the older rocks in the James River basin have been subjected to 
intense dynamic metamorphism and it is often difficult to distinguish 
between alterations due to this cause and those due solely to igneous in¬ 
trusives. The diabase dikes, and other small masses of intrusive igneous 
rock, have produced practically no effect on the sedimentary rocks along 
their contacts, but in the vicinity of the granite area the older rocks have 
been intensely altered, fly contact action. Because of the lack of good 
exposures, there are (only a few places where the contact between the 
granite and the sedimentary rocks can be observed and studied; the best 
of these is furnished by the bluffs along James River and Phelps Creek- 
in the vicinity of New Canton. The rocks in this locality will now he 
described in detail. 


STRUCTURE AND METAMORPHISM. 


107 


DETAILED DESCRIPTIONS OF CONTACT PHENOMENA. 

James River Section Across Granite Contact. 

On the south side of James River near New Canton, the contact 
between the granite and the pre-Cambrian sediments is marked by a belt 
of hornblende schists, 700 to 900 yards wide, part of which are sedimentary 
in origin, while part represent a basic border facies of the granite. In 
the absence of chemical analyses it is impossible in many cases to distin¬ 
guish between the rocks that are igneous and those that are sedimentary 
in origin, and indeed they are to a certain extent interleaved with one 
another; therefore the line drawn on the map (Fig. 2) to show the con¬ 
tact between the two formations is only approximate. On the east side, 
the hornblende schists pass into granite, while on the west they grade into 
the knotted schists which are interbedded with quartzites. 

The quartzites are described in detail on pages 16-18, and the knotted 
schists on pages 30-34. At a distance from the contact the knots or eyes 
present in the schist consist of impure siderite; about 900 yards east of 
the hornblende schists, biotite begins to take the place of siderite in the 
eyes, and within 600 yards of the hornblende schists garnets appear. The 
change is one of gradual increasing intensity of metamorphism as the 
contact is approached; but there is one exception to this rule—the knotted 
schists occurring along the east side of the quartzite, about 700 yards 
from the hornblende schists, are intensely altered in the immediate vicinity 
of their contact with the quartzite, probably because the latter rock, being 
more porous, has furnished a channel for the circulation of the heated 
solutions expelled from the cooling granite. 

About 300 yards southeast of Bremo bridge, an old tunnel, said to 
have been opened in prospecting for iron, exposes the rock along the east 
side of the quartzite. Near the schist the quartzite contains numerous 
garnets, and the quartz appears to be completely recrystallized. Adjoin¬ 
ing the quartzite there is a bed of highly garnetiferous rock, 4 to 12 feet 
wide, which grades into the typical knotted schists. The strike of the 
schists is N. 23° E. and the dip practically vertical. 

The altered rock (Spec. 456) near the quartzite is dark gray to brown 
in color, and consists of numerous red garnets, ranging up to 4 mm. in 
diameter, fine-grained quartz, radiating crystals of dark gray sillimanite, 
and a little dark green chlorite. Examined in thin sections under the 
microscope the garnets are light pink to nearly colorless, contain numerous 
inclusions, are irregular in outline, and show partial alteration to chlorite 


108 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


in their border portions and along fractures. Some are quite clear while 
others are rendered almost opaque by clouds of dust-like inclusions (mag¬ 
netite or hematite), which are frequently confined to the central portions 
leaving the borders clear. Some of the garnets also contain numerous 
included quartz grains. Quartz, which is the second mineral in relative 
abundance, has been completely recrystallized and occurs in irregular 
grains showing strain shadows. The sillimanite is mostly arranged in 
radiating clusters of prismatic crystals. Magnetite, hematite, and a little 
pyrite are present as minor accessories. 

Other exposures are furnished by several surface pits located along 
the same line of strike, a mile southwest of New Canton; and here the 
garnet rock may be seen grading on the east into the knotted schists con¬ 
taining scattered eyes of garnet. The rock (Specs. 465 and 466) from 
these openings is dark reddish-brown in color and consists chiefly of garnets 
with less quartz, sillimanite, cyanite, chlorite, magnetite, hematite, and 
pyrite present in the order named. The garnets (almandite) are large, 
imperfectly formed, and contain numerous inclusions of quartz and iron 
oxide. Under the microscope they frequently show irregular branching 
radii of clear mineral which spread out from the center and separate areas 
that are full of inclusions. As these radii recede from the center they 
branch into a vein-like network, which grades without definite boundaries 
into the surrounding ground-mass, consisting of quartz, garnet, and 
magnetite. Another form of garnet (possibly spessartite) is so full of 
dust-like inclusions of magnetite with a little quartz, that they are rendered 
almost opaque. These inclusions show a zonal arrangement, and in some 
of the garnets the zonal bands are broken and contorted as though by 
crushing. Sillimanite is present in radiating groups of fine-bladed 
crystals, and cyanite occurs in large-bladed prisms, which frequently show 
multiple twinning and contain dust-like inclusions of iron oxide. 

A garnet-sillimanite rock, similar to that just described, outcrops along 
the road near Hatcher Creek, a mile south of Gravel Hill postoffice, and 
also near the summit of Tower Hill, 2 y 2 miles southwest of Gravel Hill. 

Passing eastward from the quartzite, knotted schists are exposed in 
the river bluffs for several hundred yards. Specimen 307, taken from an 
outcrop 200 yards east of the quartzite and 800 yards from the contact, 
contains numerous eyes of biotite and only occasionally a small garnet. A 
detailed petrographic! description of the rock is given on pages 32-33. About 
300 yards farther east the schist (Spec. 306) is light bluish-gray in color, 
slightly coarser grained, and contains scattered eyes of garnet 1 to 2 mm. 


STRUCTURE AND METAM0RP1IISM. 


109 


in diameter. Specimen 305, taken about 100 yards from the contact, is of 
light gray sericitic schist containing garnets 2 to 4 mm. in diameter, and 
occasional flakes of biotite about 1 mm. in diameter. 

Near Phelps Creek and about 300 yards from the contact hornblende 
begins to be plentiful in the schist, occurring in dark green crystals that 
range from small grains up to prisms 3 or 4 mm. in length. The rock 
(Specs. 303 and 304) is mostly fine-grained and compact, breaking readily 
along closely spaced joints. The minerals distinguishable megascopic-ally 
are quartz, hornblende, chlorite, sericite, much pyrite, and a little magnet¬ 
ite. The New Canton copper mines are located directly in line of strike 
with these rocks and therefore the large amount of pyrite present is signifi¬ 
cant. Petrographic descriptions of rocks from the different copper mines 
are given on pages 250-256. 

Near the second railroad bridge over Phelps Creek and about 250 
yards from the contact the schist (Spec. 301) is a fine-grained, dark 
greenish-gray rock, speckled with numerous, well-formed, red garnets 
0.5 mm. in diameter, and containing occasional lenses of pyrite 2 or 3 cm. 
in length. With the aid of a pocket lens small needles of hornblende, 
oriented parallel to the sc-histosity, and fine-grained quartz are seen to 
make up the greater part of the rock-mass. At the Margaret mine and 
about the same distance from the contact a quartzitic rock was found 
which contains irregular crystals of dark green hornblende and light 
greenish-brown needles of sillimanite. 

In the bluff on the east side of Phelps Creek, and about 150 yards 
from the contact line shown on the map (Fig. 2), an apophysis or dike 
from the granite is exposed. It is perhaps 20 feet in width and parallels 
the inclosing schists in strike and dip. The rock (Spec. 426) is light gray 
in color, fine-grained, and highly schistose; it is composed essentially of 
white feldspar, quartz, and flakes of black biotite, which are oriented 
parallel to the schistosity and are much more plentiful in some portions 
of the rock than in others. A little garnet and magnetite may also be 
distinguished megascopically. Examined microscopically the rock is seen 
to be slightly porphyritic in texture, containing feldspars that range up to 
2 mm. in length. The feldspars are all plagioclase (albite-oligoclase or 
oligoclase) and are for the most part unstriated, but occasionally both 
Carlsbad and albite twinning c-an be distinguished. The biotite is light 
greenish-brown in color, strongly pleochroic, and some of the flakes are 
nearly as large as the feldspars. The ground-mass is composed of feldspar, 
quartz, biotite, a little chlorite, small pink garnets, and a few grains of 
magnetite and irregular zircons. 


110 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

Along the contact between the granite dike and the hornblende schists 
there is a layer of rock (Spec. 427), only a few inches thick, composed 
largely of bright green chlorite and well-formed garnets ranging up to 
0.75 cm. in diameter. Under the microscope the garnets are seen to con¬ 
tain numerous inclusions of quartz and magnetite. None of the chlorite 
is derived from the garnets, for the latter are all fresh and unaltered. 
Quartz occurs in lenticular eyes and as small veinlets between the cleavage 
planes of the chlorite. Fluid inclusions, usually with bubbles, are plentiful 
and some are comparatively large. Scattered grains of magnetite and a 
little sericite make up the accessories. 

About 50 yards southeast of the granite dike and within 100 yards 
of contact line shown on the map, the rock (Spec. 428) is light gray, 
fine-grained, close-textured, and distinctly schistose. It contains well- 
formed pink garnets ranging up to 2 mm. in diameter, and with the aid 
of a pocket lens small needles of green hornblende, quartz, and much fine¬ 
grained magnetite may be distinguished. 

Under the microscope the magnetite is seen to occur in idiomorphic 
grains which are scattered through the rock without reference to the other 
minerals; the hornblende occurs in slender needle-like prisms, occasionally 
showing sections with crystal outline; and the quartz is present in 
irregular grains filling the interstices between the other minerals. 
Scattered through this ground-mass there are a few comparatively large 
irregular crystals of acid plagioclase feldspar, ranging up to 2 mm. in 
diameter. They are very ragged in outline and poikilitic in texture con¬ 
taining numerous small inclusions of quartz and to a lesser extent of the 
other minerals. The hornblende needles occasionally project into the 
feldspars, but are usually pushed aside by them. The feldspars are partly 
oriented with their greater elongations parallel to the schistositv, they 
rarely show fine albite twinning, and are usually unstriated. A little 
chlorite is present as an alteration product of hornblende. 

The rock (Spec. 429) 30 yards south of that last described is dark 
green, even-granular, and more nearly massive in texture. Under the 
microscope it is seen to consist of hornblende, feldspar, quartz, and a little 
magnetite and pyrite, in the order named. Hornblende, which is dominant, 
occurs in irregular, elongated prisms only partly oriented parallel to the 
schistositv. The feldspar is all acid plagioclase with an index of refraction 
approximately the same as quartz, and is partly unstriated and partly 
twinned after thejilbite law. A small amount of chlorite is present as a 
secondary mineral. In the absence of chemical analyses it is impossible 
to say whether the rock is sedimentary or igneous in origin. 


STRUCTURE AND METAMORPHISM. 


Ill 


The rocks exposed in the bluffs along the east side of Phelps Creek as 
far south as the count}'’ road are all hornblende schists varying slightly in 
coarseness of texture. In places narrow dikes of quartz porphyry con¬ 
taining much biotite are interleaved with the hornblende schists. 

About 60 yards northeast of the road bridge, and within 50 yards of 
the contact as shown on the map, the rock (Spec. 433) is dark green, 
fine-grained, close-textured, and contains much pyrite in scattered cubes, 
ranging up to 3 mm. in diameter. Examined microscopically the rock is 
seen to consist of quartz, hornblende, magnetite, a little plagioclase 
feldspar, and some secondary chlorite. The magnetite is present in idio- 
morphic grains evenly distributed through the rock; the hornblende is 
almost as plentiful as the quartz, occurring in needle-like prisms that are 
imperfectly oriented parallel to the schistosity; and the quartz fills the 
interstices between the other minerals and occasionally forms lenticular 
eyes, 1 mm. in diameter. Both hornblende and magnetite are present as 
inclusions in the quartz. A little acid plagioclase showing albite twinning 
may be identified in places but is not plentiful. 

Specimen 434 was obtained from the bluffs facing the low ground on 
the south side of James River and about 75 yards east of the line of con¬ 
tact as shown on the map (Fig. 2). The rock is a dark gray, fine-grained 
hornblende schist containing streaks due to elongated segregations of the 
light-colored minerals. It is cut by closely spaced joints, which cause the 
rock to break into small rhombic shapes. Examined under the microscope, 
hornblende is seen to be dominant, occurring in slender prisms which 
occasionally show idiomorphic cross sections and are usually oriented 
parallel to the schistosity. They show good cleavage and are practically 
free from inclusions. The interstitial spaces are filled with acid plagio¬ 
clase, quartz, and magnetite. The feldspars are clear, seldom show cleavage 
or twinning, and have an index of refraction slightly less than balsam, 
corresponding to albite or albite-oligoclase. Quartz is present as a minor 
constituent, magnetite occurs in small scattered grains, and there is a little 
chlorite present as an alteration product of hornblende. 

A hundred yards farther east the hornblende schist (Spec. 435) is 
much coarser in texture. It is a heavy rock, dark green to black in color, 
and contains hornblendes ranging up to 6 mm. in diameter, numerous 
grains of magnetite, and occasional light-colored spots, consisting of fine¬ 
grained, light green epidote. Under the microscope the hornblende, which 
makes up the greater portion of the rock, is strongly pleochroic in shades 
of dark green, blue, and greenish-brown; it has good cleavage but poor 


112 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


crystal form, and frequently contains numerous inclusions of quartz and 
magnetite. Magnetite is the second mineral in relative abundance, occur¬ 
ring in small angular grains and in larger masses which occasionally contain 
inclusions of hornblende. Epidote is present in small grains and granular 
aggregates, almost colorless and only slightly pleochroic. Quartz is spar¬ 
ingly present in small grains and chlorite occurs as an alteration product 
of hornblende. 

Fine-grained hornblende schist, over 100 yards in width, intervenes 
between the coarse-grained schist and the granite, which first appears about 
400 yards east of the line showing the approximate contact between the 
sedimentary and igneous rocks. In the road half a mile south of New 
Canton a coarse-grained hornblende schist, containing a much larger per¬ 
centage of feldspar than the rock described above, is exposed close to the 
granite. 

The granite (Spec. 438), exposed in the river blufFs near the horn¬ 
blende schists, is dark gray, fine-grained, and very gneissic in structure. 
The minerals recognizable megascopically are feldspar, quartz, biotite, 
many small pink garnets, and a few scattered grains of hornblende and 
magnetite. A specimen (439) obtained about 200 yards farther east is 
much lighter in color. It has well-developed gneissic banding, and sericite 
is very prominent, while biotite is relatively scarce. Examined micro¬ 
scopically it is seen to consist of acid plagioclase, quartz, sericite, biotite, 
garnet, a very little hornblende, and the secondary minerals epidote and 
chlorite. There seems to be no potash feldspar present. Other specimens 
of the granite from this vicinity are described on pages 71-72. 

On the opposite side of James River the marginal belt of hornblende 
schist is narrower, but there are several small elongated areas of horn¬ 
blende schist included within the granite. Continuing northeast along 
the contact the belt of hornblende schists gradually becomes narrower and 
a short distance south of Fork Union entirely disappears. 

Rivanna River Section Across Granite Contact. 

The contact between the granite and the sedimentary rocks is fairly 
well exposed in the bluffs on the south side of Rivanna River, a mile north¬ 
west of Caryshrook. A quarry has been opened in the granite within 
less than 100 yards of the contact, and the rock exposed in the opening is 
described in detail on pages 75-77. The contact can be located with an 
error of less than 20 feet, but there is little if any evidence of contact 
metamorphism. The granite is probably a little finer grained than that 


STRUCTURE AX'D METAMORPHISM. 


113 


exposed in the quarry, and contains more pyrite. The sedimentary rock 
is a chloritic slate which near the contact is slightly coarser grained, more 
siliceous, and less regular in its cleavage, but all of these differences may 
be due to other causes than contact metamorphism. 

No evidence of faulting is visible, and the textural and structural 
relations of the slate indicate that it is older than the granite. The lack 
of pronounced evidence of contact action is probably due to tbe fact that 
the sedimentary rocks were intensely altered by dynamic metamorphism, 
prior to the intrusion of the granite, which must have been much cooler 
than the granite near New Canton. On pages 62-63 evidence was presented 
to show that the granite near Carysbrook was intruded and solidified at 
a later date than the granite farther south; and both the megascopic and 
microscopic evidence (see pp. 75-76) indicates that this granite was in¬ 
truded in a partly solidified condition. 

Veins. 

Quartz veins are of frequent occurrence in the sedimentary rocks near 
their contacts with the granite, and, where not exposed, their presence is 
commonly indicated by an abundance of quartz float on the surface. North 
of James River these veins contain soda-lime feldspars, muscovite, a little 
tourmaline and other minerals indicative of a magmatic origin, and they 
usually carry small quantities of gold; south of the river tourmaline is 
very abundant in many of the quartz veins. Some of the veins are accom¬ 
panied by more or less metasomatic replacement of the wall rock, and an 
extreme example of this replacement is furnished by the sulphide bodies 
near New Canton. The walls of some of the veins show evidence of mcta- 
morphic action similar to that found near the granite contacts, but on a 
smaller scale. The gold-bearing veins are described in detail in chapter A . 

Willis Mountain. 

On the southwest slope of Round Mountain (the southern knob of 
Willis Mountain) the schists in the vicinity of an intrusive diorite show 
pronounced effects of contact action. The exposures are limited to two 
shafts 40 to 50 feet deep, located about 100 yards apart in an east and west 
direction, which were sunk in prospecting for copper. The size of the 
diorite body could not be ascertained because of the insufficiency of ex¬ 
posures, but the coarseness of texture indicates that it is probably large. 

Megascopically the diorite (Spec. 390) is a massive dark gray rock 
•composed essentially of dark green hornblende in irregular prismatic 


114 


GEOLOGY OF THE GOLD BELT IX THE JAMES EIVER BASIN. 


crystals ranging np to 1.5 cm. in length, white feldspars, which frequently 
show multiple twinning, numerous red garnets about 1 mm. in diameter, 
with more or less pyrite and pyrrhotite. In places the rock is cut by 
narrow intersecting veinlets, some of which are composed of white feldspars, 
2 to 3 cm. in diameter, with more or less pyrite and pyrrhotite, while others 
consist chiefly of white, even-granular calc-ite. The latter range up to 
6 or 7 inches in thickness. There are also occasional streaks or bands due 
to the presence of unusual amounts of garnet, or, more rarely, epidote. 

Examined microscopically the hornblendes are light green in color and 
contain numerous inclusions, principally feldspar and quartz. The 
feldspars show beautiful twinning after the albite and pericline laws, and 
in composition are probably intermediate between andesine and labra- 
dorite. Most of the garnets show good crystal form; they are slightly 
altered along fractures with the production of chlorite and calcite. A 
little light brown biotite, elongated grains of rutile, ilmenite partly altered 
to leucoxene, and occasional zircons make up the minor accessories. 

The typical cyanite and quartz-sericite schists constituting Willis Moun¬ 
tain have been described in a previous chapter (see pages 25 and 27-28). 
The schist (Spec. 389) near the diorite is a light brown, fine-grained rock, 
heavily impregnated with pyrite in cubical crystals ranging up to 2 or 3 
mm. in diameter. The other minerals recognizable megascopically are 
light brown biotite, a scaly micaceous mineral, colorless to light gray or 
green (probably chlorite), a few prismatic grains of rutile, and a little 
nearly colorless cyanite. 

Under the microscope the light-colored mineral (chlorite), which is 
probably dominant, has very low interference colors and frequently occurs 
in radiating scales. The biotite is very light brown in color and rather 
weakly pleochroic; in places it contains needle-like prisms of rutile. 
Soda-lime feldspar, intermediate between andesine and labraclorite, is the 
third mineral in relative abundance and frequently shows twinning after 
both the albite and pericline laws. Cyanite is quite plentiful, rutile is 
abundant in prismatic crystals and irregular grains, and there is also much 
calcite present. The crystals of pyrite contain occasional inclusions of 
rutile but no other minerals. Zircons are present as unimportant minor 
constituents. 

OUTLINE OF GEOLOGICAL HISTORY. 

The complete geological history of this region can not be written until 
the rocks of the Piedmont province have been studied and mapped in 
greater detail; the record is fragmentary and complex, and much of it 


STRUCTURE AXD METAMORPHISM. 


115 


may never be deciphered. In the older rocks of the area, which have been 
classified as pre-Cambrian, no fossils have been found, and if they were 
ever present, they have probably been destroyed by the extensive meta¬ 
morphism that has affected the entire region. 

Pre-Cambrian. 

The history of the James River basin in pre-Cambrian times is shrouded 
in much doubt. It is not known whether the period of igneous activity, 
resulting in the formation of the basic rocks of the greenstone area, 
preceded or followed the deposition of the pre-Cambrian sediments. These 
sediments were laid down as sand and mud in shallow waters not far from 
the shore, as is indicated by the lenticular shape and sudden pinching of 
many of the quartzite beds, as well as their frequent repetition. The for¬ 
mation of pure quartz sands involves the complete decomposition of quartz- 
bearing rocks in order that the quartz grains may be separated from the 
other constituents, the latter going to form the fine clayey beds. There¬ 
fore most of the sediments were probably derived from a low-lying land 
area mantled with residual decay. These conditions, however, did not 
continue uniformly throughout the entire period of sedimentation, for the 
arkosic beds lying between Lantana and Pryors Crossroads were laid down 
under conditions that did not permit mature weathering. 

After their deposition the sedimentary beds were compressed by power¬ 
ful forces acting in a northwest-southeast direction; the effects of which 
were close folding, faulting, mashing, and recrystallization. These great 
crustal movements, which brought the pre-Cambrian period to a close, 
converted a large area within the limits of the Xorth American continent 
into land. While the crustal movements were still in progress, and 
probably as another manifestation of the same orogenic forces, large masses 
of molten rock were intruded into the sedimentary formations. 

Cambrian. 

The period of igneous activity, which resulted in the intrusion and 
differentiation of the granites and their related rocks, continued until 
after the great crustal movements had ceased. The formation of the gold 
veins is believed to represent the final stage in the differentiation and 
crystallization of the granite magma. 

The massive diorite dikes, which occur at several places in the area, 
were probably intruded during Cambrian times, but after this there ensued 
a long period of freedom from igneous activity. 


116 


GEOLOGY OF THE GOLD BELT IN THE JAMES BIVER BASIN. 


During Cambrian and early Ordovician time the area was subjected 
to extensive denudation, the products of erosion probably going to build 
up the Cambrian formations to the west. This period of denudation 
resulted in the removal of thousands of feet of overlying material and the 
exposure of the deep-seated granite. 

Ordovician. 

In late Ordovician time portions of the Piedmont region were again 
depressed below sea level to receive the sediments of that period, but it is 
improbable that all of the area has been under water since its elevation 
at the close of the pre-Cambrian. The Ordovician sediments were laid 
down on the eroded surface of the older formations, the material being 
derived from the neighboring land areas of pre-Cambrian rocks. The 
limited thickness of the coarser sediments at the base of the series, in com¬ 
parison with the overlying beds of slate, indicates that subsidence was 
rather rapid; and the presence of tuffaceous beds shows that the move¬ 
ment was accompanied bv more or less volcanic activity, although there are 
probably no igneous rocks of this age present in the district. 

The Ordovician period was closed by marked geographical changes 
which enlarged the land areas and raised the recently formed sedimentary 
beds above water. After the close of the crustal movements resulting in 
the folding and faulting of the Arvonia slate belt, the region seems to have 
entered upon a period of quiescence. While oscillations occurred in other 
parts of the country, the Piedmont portion of Virginia seems to have re¬ 
mained above water and to have suffered little if any deformation until 
after the close of the Carboniferous; and during this entire period pene- 
plaination continued uninterrupted. 

Triassic. 

It seems probable that the Piedmont peneplain was but slightly affected 
by the Appalachian revolution. The surface was warped or faulted 
sufficiently to form the elongated trough-like depressions, roughly parallel 
to the coast, in which the sedimentary beds of the Triassic (Newark for¬ 
mation) wefe laid down. It is not believed that these deposits ever covered 
a large area', Though it is possible and perhaps probable that the detached 
areas found in Piedmont Virginia were once connected with one another. 
The prevailing red color of the formations, the presence of coal beds, and 
the character of the fossils indicate that the sediments were deposited in 
fresh or brackish water and that they are not of marine origin. The- 


STRUCTURE AND METAMORPHISM. 


117 


material composing these strata was derived principally from the residual 
decay of the neighboring crystalline rocks, which must have undergone 
extensive chemical decomposition after they had been reduced by erosion 
to a nearly level plain. 

The deposition of the Triassic sediments was accompanied or imme¬ 
diately followed by the intrusion of the diabase dikes, which are of fre¬ 
quent occurrence throughout the Piedmont area. 

Since Triassic time the surface has been slightly elevated, and there 
has been a little faulting, but no important crustal movements have 
occurred; degradation has continued without interruption down to the 
present day. The detailed history of the development of the existing sur¬ 
face features is given in the chapter on physiography. 


/ 


5 


CHAPTER V. 


THE GOLD MINES OF THE DISTRICT. 

INTRODUCTION. 

Detailed descriptions of all gold mines in the district are given below, 
but because of lack of information some of the descriptions are not nearly 
so complete as others. When the region was studied by the writer most of 
the mines had long been abandoned and consequently few openings were 
accessible; development work was in progress at the Scotia, Tellurium, 
Waller, and Young American mines; an old shaft was being reopened 
on the Payne property; and a little ore had recently been mined from 
superficial workings on the Bowles tract. Some of the older mines have 
been described from time to time by geologists and mining engineers, and 
wherever information could be obtained from such sources it has been 
freely used. The mines on the north side of James River, in Goochland 
and Fluvanna counties, will be considered first, and then those located 
on the south side of the river in Buckingham County. 


MINES IN GOOCHLAND AND FLUVANNA COUNTIES. 

The Young American Mine. 

Location .—The Young American gold mine is situated in Goochland 
County about iy 2 miles north of Lantana and 6y 2 miles northeast of 
Columbia. 

History .—The Young American, formerly known as the Gilmer mine, is 
said to have been discovered about 1869 by a Mr. Aldrich, who at that time 
was operating a saw mill on the property. After a little prospecting he sank 
a shallow shaft on a vein, now known as the “House” vein, and then built 
a small stamp mill to crush the ore. The mill had wooden stamp-stems 
with iron shoes, and was operated by the same engine that furnished 
power for the saw mill. Mr. Aldrich is reported to have made some money 
from the mine, but only worked it for a short time. Later gold was 
discovered in the branch that runs through the property and sluice and 
rocker washing was carried on during the period between 1871 and 1874. 































































THE GOLD MINES .OF THE DISTRICT. 


119 


In 1880, the Tagus Gold Mining Company began development work 
and continued operations for three years. About 100 tons of ore found on 
the surface were hauled to the Belzoro mill and stamped, yielding a return 
of $5.00 per ton. The “House” vein was developed and stoped down to 
water level for a distance of approximately 600 feet along the strike, and 
some small lenses of quartz, paralleling the “House” vein about 100 feet 
to the west, were exposed by an adit and mined. The “Sulphur” vein, 
about 300 yards west of the “House” vein, was explored, several small 
shafts sunk, and much of the vein above water level stoped out. A 4-foot 
Bryan mill was installed to pulverize the ore. As no records are now 
available it is impossible to give authentic information in regard to the 
production and average value of the ore mined. According to one report 
the average value of the ore obtained from the “House” vein was $5.27 
per ton, but another states that it averaged $10.00 per ton. They all agree 
that the ore from the “Sulphur” vein was lower in value. 

From 1885 to 1909, when the present company bought the property, 
the mine passed through several hands, and while occasional attempts at 
development were made, very little ore was milled. It is reported that 
a cyanide plant was in operation in 1893, but with what success is not 
known.® The present company has reopened several of the old shafts and 
drives, sunk 2 shafts on the “Sulphur” vein to a depth of 84 and 100 feet, 
respectively, and done considerable development work, chiefly on the 
“Sulphur” vein. After making trial runs with the old Bryan mill, a new 
building was erected in 1910 and a Lane mill installed, but only about 
1,500 tons of ore have as yet been milled. 

Present equipment .—The mine is equipped with 2 shaft houses, a mill, 
and several other buildings. A steam hoist is located at each of the shaft 
houses, and there is an air compressor to furnish compressed air for the 
drills. The mill contains a Blake crusher, feeder, slow-speed Lane mill, 
and 2 Traylor concentrating tables. 

Underground development .—The “Sulphur” vein, having a strike of 
N. 30° E., and an average dip of about 40° toward the southeast, is 
developed by 2 hoisting shafts and several air shafts, with underground 
drives that connect them and extend for a distance of 500 feet or more 
along the vein. The “Sulphur” shaft, sunk on top of the hill, in the 
hanging wall at a distance of 60 feet from the outcrop, is vertical to a 
depth of 80 feet where it intersects the vein, and then follows the vein on 

aNitze, H. B. C., and Wilkins, H. A. J., Gold Mining in North Carolina and 
Adjacent South Appalachian Regions, Bull. 10, N. C. Geol. Survey, 1897, p. 38. 



120 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


an incline for about 42 feet, making the total depth below the surface 100 
feet. About 75 feet from the surface, drives extend in either direction along 
the vein, connecting with the other shafts, and near the bottom of the 
incline 2 short drives run northeast and southwest. The “II. V." shaft, 
near the branch, 340 feet northeast of the “Sulphur" shaft, is vertical and 
83 feet deep, the first 30 feet being on the vein, which here is nearly 
vertical for that distance. At a depth of 30 feet from the surface a drive 
along the vein connects with the “Sulphur” shaft, and 54 feet from the 
surface an 18-foot cross-cut running southeast intersects the vein, which at 
this point is further exposed by 2 short drives in either direction. 

Practically all the stoping has been confined to the upper portion of 
the vein above the drive connecting the two hoisting shafts, and very little 
ore that would pay the cost of mining and milling remains in that part of 
the mine. 

The “House” vein, outcropping about 250 yards east of the “Sulphur” 
shaft, is not at present accessible, but the old stopes and surface cuts have 
a strike of 1ST. 22° E. A shaft, sunk about 350 yards southeast of the 
“Sulphur” shaft, did not strike the vein. Several adits have been driven 
under the hill near the north end of the old workings, and though they 
were not carried far enough to intersect the “House” vein, they expose a 
number of large lenses and stringers which approximately parallel that 
vein. The larger lenses encountered have been mined out above the water 
level. 

General description of the geology .—There are almost no surface out¬ 
crops in the vicinity of the Young American mine, but there are many 
exposures along Big Byrd Creek, which cuts directly across the strike of 
the rocks, 3 miles southwest of the property. On the east side of the 
creek, about half a mile south of Bowles’ bridge, rocks outcrop which are 
apparently identical with the country rock exposed in the underground 
workings of the mine, and they are in the same line of strike. These rocks 
are intensely metamorphosed schists and gneisses, derived from bedded 
sedimentaries, which were probably arkosic sandstones and grits. About 
three-quarters of a mile southeast of the mine this series of altered sedi¬ 
mentary rocks passes into and is interbedded with quartzites, which are in 
places highly ferruginous, containing both specular hematite and magnetite. 
Crystals of magnetite, consisting of octahedrons 1 cm. and less in diameter, 
which have weathered from the underlying rock, are found on the surface 
300 yards northeast of the veins, and at several other localities on the 
property and in its immediate vicinity. The wall rock exposed in the mine 
usually contains much fine-grained magnetite. 


THE GOLD MINES OF THE DISTRICT. 


121 


The hornblendic border facies of the main granite batholith is exposed 
about a mile southeast of the mine, and what is probably a tongue from 
the latter comes within three-quarters of a mile or less, outcrops of granite 
occurring along the branch that runs about that distance northeast of 
the mine. 

Two varieties of gneiss are exposed in the underground workings: The 
dominant type is a dark greenish-gray, fine-grained rock, usually banded, 
and composed essentially of quartz, feldspar, hornblende, biotite, and 
chlorite, with smaller amounts of magnetite, calcite, and sericite; the 
other, which is similar except for the absence of most of the iron-bearing 
silicates, is a fine-grained, light gray rock, composed essentially of quartz, 
feldspar, sericite, and smaller amounts of chlorite and calcite. The chief 
mineral constituents in these rocks, while varying somewhat in their 
relative proportions, are always the same. 

In the openings on the “Sulphur” vein, the light-colored gneiss occurs 
as a bed, varying from l 1 /^ to 8 feet in thickness and lying between strata 
of the darker gneiss. It was also found on the dumps of some small pits 
and shafts near the line of strike of the “House” vein, about 200 yards 
south of the Dietz shaft, but in most openings on the property that are 
now accessible the dark hornblendic rock is the variety exposed. 

There are two principal veins on the property that have been worked 
for gold, the “Sulphur” and the “House” veins. In the vicinity of the 
“House” vein there is a large number of small stringers and lenses which 
have been mined to a limited extent. 

The “Sulphur” vein at the surface has an average strike of about 
N. 40° E., which is approximately the same as that of the country rock, 
but locally there is considerable variation, and in the underground work¬ 
ings near the Chittenden air shaft there is a sharp change in strike from 
N. 21° to 53° E. The dip is toward the southeast, changing from almost 
vertical in places near the surface to an angle of 30° in some of 
the lower workings, the average for the first 150 feet from the outcrop 
being about 50°. The width varies from 6 feet down to a few inches, and 
the average is probably between 2 and 3 feet. Where the vein is several 
feet wide it consists of a single mass of quartz, but elsewhere it frequently 
breaks up into a number of approximately parallel stringers and lenses, 
forming a belt 6 or 7 feet wide in which the country rock between the 
veinlets may be more or less mineralized. (See figs. 6 and 7.) In one 
instance noted, the veinlets instead of being parallel to the general inclina¬ 
tion of the vein cut across it in such way as to suggest their formation in 


122 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

a zone of shear faulting (see fig. 9, p. 130). Where exposed in the under¬ 
ground workings, the “Sulphur” vein occurs in the light-colored gneiss 
and also in both the overlying and underlying, dark, hornblendic gneiss. 

The “House” vein, 200 to 300 yards east of the “Sulphur” vein, has a 
strike of about 1ST. 22° E., which would cause the two veins to intersect 
if they both maintain their courses toward the northeast. The “House” 
vein is said to have an average width of 5 or 6 feet, but as the old workings 
have caved and are not now accessible this statement could not be verified. 
The strike was determined by means of the old surface cuts and caved 
stopes along the outcrop. Hear the southwestern end of the old workings 
the country rock seems to be chiefly the light-colored gneiss or schist, but 
where the adits have been driven under the hill near the northeastern 
extension of the vein, the country rock, wherever exposed, is a dark green 
hornblendic gneiss, similar to that found in the openings on the “Sulphur” 
vein. 

The adits, above mentioned, were not carried far enough to strike the 
“House” vein, but they cut through a large number of lenticular veinlets 
that apparently parallel the main vein. These veinlets range from 
stringers a fraction of an inch in width up to lenses 2 feet thick and 25 
feet or more in length, and are pegmatitic in character, frequently carry¬ 
ing much plagioclase feldspar—a mineral which is only occasionally present 
in the “Sulphur” vein. No openings have been made much below water 
level, but where the lenses have been mined their dip is practically vertical. 

While the veins and country rock at the Young American mine are 
much broken by jointing, and there is in places a small amount of fault¬ 
ing along these joints, there is no evidence of important faulting since 
the formation of the veins. The irregularities in the strike and dip which 
were mentioned above are believed to be due to faulting and fracturing 
prior to the formation of the veins, which left openings or lines of weakness 
along which the solutions that deposited the ores were able to penetrate. 

In addition to the veins described above, several quartz veins carrying 
considerable tourmaline outcrop in the vicinity of the mine, but at the 
surface they contain only traces of gold and therefore practically no 
development work has been done on them. 

Detailed descriptions of the veins and wall rock .—At the bottom of the 
incline from the “Sulphur” shaft, about 100 feet from the surface and 65 
to 75 feet below the natural water level, the vein consists of lenses and 
irregular masses of quartz distributed over a belt 5 to 6 feet in width, which 
is here confined to the bed of light-colored gneiss. A sketch, drawn to scale, 


THE GOLD MINES OF THE DISTRICT. 


123 


showing the distribution of vein quartz and the structural relations of the 
wall rock, is given in fig. 6. Only a short distance above this point the 
quartz begins to collect together so as to form a single well-defined and 
continuous vein. 


N. W.«* 


*-S. E. 



0 1 


SCALE 

l 3 


4 5 Feet 


Fig. 6.—Vertical section showing vein at bottom of “Sulphur” incline, Young 

American Mine. A, dark-colored gneiss; B, partly decomposed gneiss; 

C, light-colored gneiss; D, vein quartz. 

The vein quartz is white, translucent and coarsely crystalline. It con¬ 
tains a little over 1 per cent, of pyrite, slightly cupriferous and sometimes 
associated with fine-grained magnetite, and, rarely, crystals of white 
feldspar difficult to distinguish from quartz are present. In places there 
are small masses of chlorite and flakes of biotite which probably represent 
altered inclusions of country rock. A carefully collected, average sample 
assayed $1.34 in gold with no silver. In the vicinity of the quartz masses, 
the gneiss is also mineralized to a considerable degree, containing dis¬ 
seminated grains of pyrite and many small veinlets of quartz which de¬ 
crease in number and size on passing away from the vein stringers, so that 
they are not noticeable at a distance of 4 or 5 feet. These veinlets range 
from half an inch down to those that are microscopic in size and usually 



















124 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

parallel the schistosity; the pyrite occurs in small grains and elongated 
masses less than 1 cm. in diameter and is frequently more plentiful along 
the quartz veinlets. 

The dark-colored gneiss overlying the bed of lighter color, while 
apparently fresh near the contact, passes gradually into partially decom¬ 
posed rock a short distance above (see fig. 6), and this illustrates the 
great depth to which weathering has reached in this area. As this was 
the deepest opening accessible in the area when the region was studied 
by the writer, average samples of the different rocks exposed at this point 
were carefully taken. A partial analysis of the vein quartz was made, and 
complete analyses of the two varieties of gneiss and also of the partly 
decomposed gneiss. For convenience in comparison these analyses are 
assembled in the table given below, which is followed by a detailed petro¬ 
graphic description of the rocks. The analyses are arranged in the order 
of their relative distance from the vein quartz, which is also the order of 
decreasing mineralization as is indicated by the decreasing percentages 
of Si0 2 and FeS 2 . 


Analyses of vein and wall rock from the Young American Gold Mine. 



1 

II 

III 

IV 

SiO. 


75.72 

66.69 

63.68 

Al.,0, . 


13.14 

15.25 

16.11 

Fe.O-j . 


0.33 

1.46 

4 05 

FeO". 


1.44 

3.78 

2 67 

MgO . 


0.31 

2.89 

3 55 

CaO . 


1.07 

2.33 

2 18 

Na.O . 


3.77 

3 56 

3 75 

K.,0 . 


1.75 

1 65 

1 43 

H„0— . 


0.12 

O 33 

1 07 

H.O+ . 


1.00 

1 26 

0 96 

T A . 


0.10 

0 41 

0.46 

ZrO, . 


0.01 


cob. 


0.63 

0.36 


PA . 

. / . . . 

0.04 

0.06 

0.06 

S . 




Trace 

Cr A . 




0 01 

va". 




0 01 

MnO . 


0.02 

0 09 

0.08 

BaO . 


0.02 


Li A . 


Trace 

Trace 

Trace 

Cu . 

Trace 

Trace 

Trace 

Trace 

FeS, . 

1.13 

0.62 

0.09 

Trace 

Gold (ounces) . 

0.065 

Trace 

Trace 

Trace 

Silver (ounces) . 


Trace 










99.99 

100.21 

100.07 












































































THE GOLD JUNES OF THE DISTRICT. 


125 


I. Vein quartz (D in fig. 6). This sample contained 0.87 per cent, iron in excess of 
the amount necessary to form pyrite, the excess being present as a 
constituent of magnetite and chlorite. Determinations made by E. E. 
Burlingame and Co. 

II. Light-colored gneiss (C in fig. 6). Analysis made by Roger C. Wells; gold 
and silver determined by E. E. Burlingame and Co. Another sample of 
this rock assayed by the writer gave 0.05 oz. of gold per ton. 

III. Dark-colored gneiss (A in fig. 6). Analysis made by Roger C. Wells; gold 

and silver determined by the writer. 

IV. Decomposed dark-colored gneiss (B in fig. 6). Analysis made by Roger C. 

Wells; gold and silver determined by the writer. 

The dark-colored gneiss is gray, and in places has a slightly greenish 
tinge. It is fine-grained, even-grannlar, and the minerals are imperfectly 
segregated into parallel bands 1 mm. or less in width, which are frequently 
folded or contorted to a small extent. The dark bands are due to the 
presence of biotite, chlorite, hornblende, and magnetite; the light bands 
are composed chiefly of quartz with a little sericite. Pink garnets, about 
2 mm. in diameter, more or less crushed and elongated parallel to the 
schistosity, occur scattered through the rock, and a little pyrite may also 
be distinguished. 

Examined microscopically, the rock (Spec. 112-A) has a well-defined 
schistose structure, the different minerals being oriented parallel to their 
greatest elongation, and largely segregated into bands which differ from 
one another in size of grain as well as in mineral composition. In the 
order of relative abundance the minerals present in the slide are quartz, 
feldspar, biotite, chlorite, hornblende, magnetite, carbonate (calcite ?), 
pyrite, and sericite. The quartz grains are usually clear, show no optical 
distortion, and contain occasional rutile needles, and other minute inclu¬ 
sions. Some of the larger bands consist almost exclusively of quartz, the 
individual grains of which they are composed being slightly larger than 
those in the rest of the rock. These bands are probably chiefly due to the 
recrystallization of silica originally present in the rock, but may be formed 
in part from quartz brought in by the vein-forming solutions. Much 
feldspar (probably oligoclase) is present in the slide. It is partly 
kaolinized, seldom shows twinning, and, as the index of refraction is 
practically the same as quartz, is hard to distinguish from the latter. The 
biotite is light brown to greenish-brown in color, strongly pleochroic, and 
frequently shows partial alteration to chlorite. There is much chlorite 
present, occasionally showing multiple twinning, and it appears to have 
been derived chiefly from the hornblende. Hornblende occurs in two 
varieties; one light green in color, the other light brown to nearly color¬ 
less. It is extensively altered with the formation of carbonate (calcite ?) 
and chlorite. In places numerous fragments of hornblende occur, 


126 GEOLOGY OF THE GOLD BELT IN THE JAMES BIVER BASIN. 

separated and completely surrounded by calcite, which extinguish simul¬ 
taneously under crossed nicols, showing that all of the fragments belong 
to a single crystal which has undergone partial alteration. Much fine¬ 
grained magnetite is present and occasionally a little pyrite. 

In the chemical analysis, the excess of magnesium over calcium 
indicates that the rock is sedimentary in origin, and this is confirmed by 
the structural relations. Chemical analysis as well as microscopic exam¬ 
ination shows that weathering has begun to affect the rock even where 
freshest. In comparing the analysis of the freshest material with that of 
the partly decomposed rock, it is seen that the chief changes, aside from 
kaolinization of the feldspars, have been the removal of carbonate and the 
oxidation of much of the ferrous iron to the ferric condition. 

As the light-colored gneiss at this point is nearer to the quartz stringers 
than the darker gneiss, it contains more quartz veinlets and a larger 
amount of pyrite. The rock (Spec. 112-C) is white to light gray in color, 
and distinctly banded, though this feature is not as noticeable as in the 
darker gneiss, because of the lack of contrast in the colors of the principal 
constituents—quartz, sericite, and feldspar. The bands are frequently 
contorted, especially in the vicinity of the quartz stringers and lenses. 
The small veinlets of quartz, ranging up to about 1 cm. in diameter, are 
usually parallel to the banding, but in places cut directly across. Pyrite 
occurs in grains and small lenticular masses elongated parallel to the 
schistosity, is sometimes associated with magnetite, and is more plentiful 
in the vicinity of the quartz veinlets. A little chlorite, occasional pink 
garnets, crushed and elongated parallel to the schistosity, and very rarely 
needles of black hornblende, make up the minor constituents which are 
recognizable in the hand specimen. 

Microscopic study shows that the principal mineral constituents in the 
order of their relative abundance are quartz, sericite, feldspar, chlorite, 
and carbonate (calcite ?). The textural characteristics and mineral com¬ 
position of the rock are similar to the darker gneiss (112-A) excepting 
that quartz and sericite are more abundant, while biotite and hornblende 
are essentially absent. The minerals, particularly sericite, are largely 
'segregated into parallel bands. The feldspars are not so extensively 
kaolinized as in the overlying rock, but appear to be similar in composition. 
They are seldom striated and have an index of refraction only a little below 
quartz, indicating that they are probably near albite-oligoclase in com¬ 
position. Orthoclase is rare if present, and probably most if not all of the 
potash content is in the form of sericite. An analysis of this rock is given 
in column II of the table on page 124. 


THE GOLD MINES OF THE DISTRICT. 


127 



SCALE 

0 1 2 3 4 5 Feet 

I I l- 1 -t- . - .-3 


Fig. 7.—Sketch showing distribution of vein quartz in light- and dark-colored 
gneisses at the Young American Mine. A, dark-colored gneiss; B, vein quartz; 
C, light-colored gneiss. 

The sketch shown in fig. 7 indicates the appearance of the face in the 
drive running southeast near the bottom of the “Sulphur” incline. The 
location is about 10 feet above the sketch shown in fig. 6, and 18 feet 
southeast. Here the bed of light-colored gneiss is thinner, and the vein 
quartz chiefly distributed in the overlying and underlying gneiss. The 
quartz vein, about a foot wide, shown in the lower left hand corner of the 
sketch, contains chalcopyrite as w r ell as pyrite. Mr. Ivnutzen, Superin¬ 
tendent of the Young American mine, states that samples from this 1-foot 
vein yielded from $11.20 to $24.00 gold per ton, and that a picked speci¬ 
men showing chalcopyrite carried $50.00 per ton. The value of the ore 
in this drive seems to vary greatly within short distances; an average 
sample, obtained from 6 buckets (about 1)4 tons) after passing through 
the crusher, assayed $8.00, while a similar sample from 4 buckets of ore 

















r 


128 GEOLOGY OF THE GOLD BELT I FT THE JAMES BIVER BASIN. 

that were obtained as a result of the next round of blasting gave only $1.00 
per ton. According to Mr. Knntzen the gold content is highest where 
chalcopyrite is found. 

A hand specimen (116) was obtained from this drive showing the two 
varieties of gneiss in contact. The line of contact is quite sharp and is 
parallel to the banding which is slightly contorted. The rock is cut by 
narrow veinlets of quartz commonly parallel to the banding and in places 
showing a tendency to follow the contact between the light and dark gneiss, 
but which frequently cut directly across the schistosity. A thin section 
was made to show one of these veinlets about 0.5 cm. in width. Under 
the microscope, numerous liquid- and gas-filled cavities can be seen in the 
quartz, usually arranged in rows or planes that occasionally pass without 
interruption from one crystal individual to another. Some of the cavities 
contain bubbles in constant and rapid vibration. The dark variety of 
gneiss, which in the slide forms the walls of the veinlet, is similar to that 
described above. The constituent minerals are quartz, feldspar, biotite, 
hornblende, chlorite, sericite, and calcite, and a little pyrite, magnetite, and 
ilmenite partly altered to leucoxene. A small colorless garnet, showing slight 
anomalous biaxial character, is also present in the slide. In several places 
pyrite occurs, bordered by a narrow rim of magnetite, which was probably 
produced under conditions of partial oxidation. 

The smaller veinlets, especially in the light-colored gneiss, show a 
strong tendency to form lenses, but they are not as perfectly developed as 
those in the “Middle” vein at the Tellurium mine. A photograph of some 
small lenses in light-colored gneiss from the “Sulphur” shaft is shown 
in PI. X, fig. 2. 

Pyrite is more plentiful in the light-colored gneiss than in the dark 
variety, and occurs in elongated grains or broken lines parallel to the 
banding. Some secondary pyrite was noted along joint planes in both the 
vein quartz and the country rock. 

Near the bottom of the “Sulphur” shaft, about 80 feet from the sur¬ 
face and just above the incline, the quartz vein is 2 feet wide, and the 
dark gray, biotite-sericite gneiss, which forms the foot wall, is heavily 
impregnated with pyrite and contains occasional lenses and veinlets of 
quartz. Mr. Knutzen obtained assays of $3.60 gold per ton from this 
mineralized wall rock, which extends several feet from the vein. 

In PI. X, fig. 1, is shown a photograph of one of the quartz veinlets 
in contact with the heavily mineralized gneiss. A crystal of light blue 
cyanite 6 mm. wide and 3 cm. long extends from the wall rock out into 


VIRGINIA GEOLOGICAL SURVEY. 


PLATE X. 



1'ig. 1.—Photograph showing cyanite and muscovite in vein quartz from the Young 
American mine. C, cyanite; M, muscovite; Q, vein quartz; P, pyrite; G, 
gneiss. 



Fig. 2.—Lenses of vein quartz in gneiss from Young American mine. 
CYANITE AND MUSCOVITE IN QUARTZ, AND QUARTZ LENSES IN GNEISS. 








THE GOLD MINES OF THE DISTRICT. 


129 


the quartz. The vein quartz also contains a little white feldspar, flakes 
of muscovite, and a few specks of chlorite. Caleite occurs in the gneiss 
and is partly concentrated along the contact with the veinlet. Very little 
pyrite is present in the quartz, but it is abundant in the gneiss, where it 
occurs in bands and broken lines parallel to the schistosity, which is much 
folded in the vicinity of the veinlet. Pieces of vein quartz, similar to that 
just described, but containing both cyanite and tourmaline, were found 
on the surface. The cyanite is sparingly distributed through the quartz in 
light blue prismatic crystals 3 to 4 mm. wide and 1.5 cm. long; and the 
tourmaline occurs in black prisms 2 to 3 mm. in diameter, which usually 
radiate in all directions from a common center. Elsewhere cyanite was 
noted in the metamorphosed wall rock near the veins, but in the specimens 
described above it occurs in detached prisms within the vein quartz itself. 

In the foot-wall, 5 or 6 feet from the vein at the bottom of the 
“Sulphur” shaft, the rock is a dark gray, fine-grained, even-granular 
gneiss, with well-marked banding. It shows no evidence of mineralization, 
pyrite as well as the quartz veinlets being absent. The light-colored bands 
in the rock range up to 2 mm. in width and are composed chiefly of 
feldspar and quartz, though they are not as a rule distinguishable from 
each other in the hand specimen. The dark bands are narrower and con¬ 
sist essentially of biotite, hornblende, and chlorite. Much magnetite is 
present in small grains, but no garnets were noted. Under the microscope 
the rock is similar to the dark variety of gneiss described on pages 125-126 r 
except that feldspar seems to be dominant over quartz, possibly because of 
the absence of silieification by vein-forming solutions. In the order of 
their relative abundance the minerals present are feldspar (probably 
andesine or oligoclase-andesine), quartz, hornblende, biotite, chlorite, cal- 
cite, and magnetite, with a few scattered grains of zircon and titanite. 
The hornblende occurs in two varieties, one green in color, and the other 
yellowish-brown. The latter, which is subordinate in amount, has parallel 
extinction and is present in long ragged prisms. It is one of the ortho¬ 
rhombic amphiboles. The other minerals present no unusual character¬ 
istics. 

The drive connecting the “Sulphur” and “H. V.” shafts exposes an 
offset of 10 to 15 feet in the course of the vein just north of the “Sulphur” 
shaft, the space between being occupied by a zone containing numerous 
lenses and irregular masses of quartz. At the shaft the vein is standing 
nearly vertical. The sketch given in fig. 8 shows the distribution and 
shape of the quartz masses exposed on the east side of the drive about 15 
feet north of the shaft. The country rock here is the dark variety of 
gneiss, and is much folded and contorted. 


130 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


N. E. ■<- -VS. W. 



0 3 6 9 12 Inches 

i - -:- i h - , d— ~i 


Fig. 8.—Vertical section showing distribution of vein quartz in a sheared zone at 
the Young American Mine. 


S. E. -- -N. W. 



Fig. 9.—Sketch showing distribution of quartz lenses in a zone of shear faulting 
Young American Mine. 




































THE GOLD MINES OF THE DISTRICT. 


131 


There is another sharp break in the course of the vein near the 
Chittenden shaft where the strike suddenly changes from N. 21° to 
53° E., and at this point there is a similar breaking up of the vein into 
separate lenses and irregular masses. A sketch of the vein, exposed in a 
small opening opposite the Chittenden shaft, is given in fig. 9. The 
distribution of the quartz lenses relative to the average strike and dip of 
the vein suggests that they were formed in a zone of shear faulting. The 
country rock is the dark variety of gneiss which is slightly mineralized in 
the immediate vicinity of the vein. A sample from the hanging wall, 
assayed by the writer, gave 0.03 ounces gold per ton. A 12-ton mill run of 
mineralized gneiss from the foot-wall of the vein, in the main drive about 
40 feet northeast of this place, is said to have averaged $3.60 gold per ton. 

In the “H. Y.” shaft, the vein is nearly vertical to a depth of 30 feet, 
at which point it begins to dip toward the southeast and leaves the shaft. 
(See fig. 10.) Where the vein is exposed by the cross-cut from the shaft, 
54 feet below the surface, it is 3 to 6 feet in width, dips at an angle of 40° 
toward the southeast and has a strike of about N. 30° E. The wall rock 
on both sides of the vein is the dark variety of gneiss, much decomposed, 
and showing no evidence of mineralization, but Mr. Knutzen states that a 
sample from the hanging wall assayed $0.50 per ton. The vein quartz is 
irregularly mineralized, containing pyrite, chalcopyrite, and occasionally 
a very little sphalerite. 

The sulphides are strung out in narrow lines or small lenticular masses 
approximately parallel to the walls, and the sphalerite usually occurs 
separate from the other ore minerals instead of being intermixed with 
them. A little white feldspar occurs in some of the quartz, but appears 
to be chiefly confined to the border portions of the vein. Very rarely, 
black tourmaline is present in small radiating prisms, and one specimen 
was found with a speck of free gold about 0.4 mm. in diameter, resting on 
the tourmaline, which is imbedded in quartz and surrounded by a small 
amount of limonite derived from pyrite. Pieces of the vein frequently 
show imperfect crystals of quartz lining joint planes, and several small 
vug-like openings w'ere seen in which the walls were lined in a similar 
manner. It is probable, however, that these openings are due to the 
oxidation and removal of pyrite rather than to spaces that were left un¬ 
filled when the vein was originally formed. Some of these vug-like spaces 
contain a little pyrite, more or less oxidized, and in places the sulphide has 
a crystal form closely resembling marcasite. Small flakes of chlorite and 
muscovite occur in parts of the vein. 


132 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


The gold is not evenly distributed throughout the vein, much of it being 
apparently concentrated in the sulphides. Mr. Knutzen obtained an assay 
of 5.8 ounces of gold per ton from a piece of the chalcopyrite. A mill run 
made on 8 tons of ore from the vein at this point averaged $3.20 per ton. 

The “H. V." shaft passes through the bed of light-colored gneiss about 
15 feet below the cross-cut to the vein. At this point it is 3 to 4 feet thick 

and dips towards the southeast 
at an angle of about 25° (see 
fig. 10). The rock is white 
and highly lustrous on fracture 
surfaces parallel to the cleav¬ 
age. In addition to the quartz 
and sericite, a little fine¬ 
grained pyrite and rarely small 
needle-like prisms of horn¬ 
blende are sparingly scattered 
through the rock. In thin sec¬ 
tion (Spec. 506) under the 
microscope, the rock shows 
distinct banding due to the 
partial localization of sericite 
in narrow parallel bands. 
Quartz, the dominant mineral, 
occurs in small rounded grains 
associated with feldspar 
(albite ?), which is usually 
clear and unstriated, though 
mutiple twinning may be seen 
in places. Small cubes of 
pyrite and a very little chlorite 
make up the accessory min¬ 
erals. 

The rock exposed in the 
bottom of the shaft is a dark 
greenish-gray gneiss in which 
the banding: is only imper- 



10 

_ > _ 


SCALE 

20 


30 


40 Feet 


Fig. 


10.—Vertical section through “H. V.” 
shaft, Young American Mine. V, vein; A, 
decomposed gneiss; B, dark-colored gneiss; 
C, light-colored gneiss. 


fectly developed. In thin section (Spec. 503), the minerals identified in 
order of their abundance were hornblende, feldspar, quartz, biotite, chlorite, 
magnetite, and a little carbonate. The hornblende is light green in color 













THE GOLD MINES OF THE DISTRICT. 


133 


and has rather low interference colors. The cleavage is good but the 
crystals are irregular in outline and contain occasional inclusions of the 
other minerals. Alteration to chlorite is frequently shown. Part of the 
feldspar is twinned after the albite law, but much of it is unstriated and 
difficult to distinguish from quartz, which it closely resembles in refraction 
and birefringence. The biotite is light brown in color and strongly pleo- 
chroic. Angular grains of magnetite are scattered through the slide and 
a little carbonate is present. 

The small amount of carbonate contained in the gneiss just described, 
and its absence in the light-colored variety from the “H. V.” shaft, is in 
marked contrast to its abundance in specimens from other parts of the mine. 
The relative scarcity of carbonate in these rocks may be due to greater 
depth below water level—75 or 80 feet—or possibly it is to be explained 
by distance from the vein—about 25 or 30 feet. 

In the southwest end of the mine near the “12th of May” shaft the 
vein is 2 inches to 3 feet wide and averages about 14 inches. For some 
distance it splits up into two separate stringers which in places are slightly 
contorted. Slickensides were noted in a number of localities, but the vein 
is little affected by faulting. Radiating prisms of black tourmaline are of 
rare occurrence, being found occasionally in quartz from near the shaft. 
Most of the wall rock in this portion of the mine shows much decomposi¬ 
tion, but in the floor of the drive 125 feet southwest of the “Sulphur” 
shaft there is a little fresh gneiss exposed on the foot-wall side of the vein. 
The rock (Spec. 118) is white to light greenish-gray in color where fresh, 
but along joint planes it is stained brown from the alteration of iron 
minerals, and in places the stain extends several inches from the fracture 
surface. Quartz and feldspar are the chief minerals with chlorite, horn¬ 
blende, calcite, biotite, cyanite, and sericite present in smaller quantity. 
Cubes and irregular grains of pyrite are sparingly disseminated through 
the rock, and upon assaying an average sample it yielded 0.01 ounce of 
gold per ton. 

Examination under the microscope shows that part of the quartz is 
present in small veinlets, probably as a result of mineralization by the 
vein-forming solutions. Part of the feldspar shows albite twinning, and is 
unquestionably acid plagioclase, but in most cases the twinning is absent 
and identification could not be made with certainty. There probably is 
some orthoclase present, but most of the unstriated feldspar is plagioclase. 
There are large areas in the thin section consisting of intercrystallized cal¬ 
cite and chlorite, possibly derived from hornblende, but some of the chlorite 


134 GEOLOGY OF THE GOLD BELT IN THE JAMES KIVER BASIN. 

was clearly formed from biotite. Areas of fine scaly sericite are present, 
some of which contain nuclei of unaltered mineral—probably cyanite. 

The ore seems to occur in shoots that dip steeply toward the left as 
they descend along the vein, but this can not be verified until more develop¬ 
ment work has been done. One such ore shoot was found near the 
“Sulphur” shaft, and another between the “H. V.” and the Chittenden 
shafts. 

In the adits that were driven under the hill toward the “House” vein 
most of the country rock is soft and decomposed, but at several places 
where the floor of an adit approaches water level, fresh rock is encountered. 
Both the fresh exposures and the residual decay indicate that the rock is 
normally a hornblendic gneiss or schist, essentially the same as the dark 
variety of gneiss found in the underground workings on the “Sulphur” 
vein. In the immediate vicinity of the numerous veinlets and lenses which 
are exposed in the adits and have been worked to a limited extent for gold, 
the country rock exhibits certain important variations from the normal, 
which later will be described in detail. 

The country rock, exposed near the portal of a prospecting tunnel that 
was started on the northwest side of the hill, is almost massive in the hand 
specimen (502), but shows a distinctly schistose structure under the micro¬ 
scope. Megascopically it is a dark greenish-gray, fine-grained rock, con¬ 
taining numerous idiomorphic garnets 1 to 2 mm. in diameter, and occa¬ 
sional rare grains of pyrite. The constituent minerals are amphibole, 
quartz, soda-lime feldspar, chlorite, magnetite, carbonate, a very little 
greenish-brown biotite, and quartz. In thin section most of the amphibole 
is green to bluish-green in color, and probably corresponds to common horn¬ 
blende, but there are two other varieties present in small amounts. One is 
pleochroic in shades of light pink and dark greenish-gray, the interference 
colors being blues and greens of the second order, and is monoclinic in 
crystallization; the other is light yellowish-brown in color and ortho¬ 
rhombic in its crystallization. The latter mineral is present in much of 
the gneiss in this vicinity, but always in very small quantity. Hornblende 
is dominant over the other minerals and usually shows parallel orientation. 
Some of the feldspar (andesine) shows albite twinning, but much of it is 
unstriated and difficult to distinguish from quartz, which it resembles in 
refraction and birefringence. Much of the chlorite shows multiple 
twinning. 

The veinlets and lenses vary from a fraction of an inch in thickness 
up to masses 2 feet wide and 25 feet or more in length. The shape of some 


THE GOLD MIXES OF THE DISTRICT. 


135 


of the old openings suggests that even larger lenses may have been removed 
by previous mining operations. The veinlets are exposed in the adits on 
both sides of the hill, but are more plentiful in those that were driven 
from the west side. The larger lenses consist essentially of quartz, with 
pyrite and a little feldspar, the latter being chiefly concentrated near the 
walls though also occurring throughout the mass. In some of the smaller 
veinlets feldspar in places is dominant over quartz. Along fractures in 
the quartz-feldspar rock, much white mica is found in flakes 6 or 7 mm. in 
diameter with no regular orientation. While these crystals are quite large 
and may be primary muscovite, their localization along fractures indicates 
that they are probably secondary, derived from feldspar. Pyrite is very 
unequally distributed, occurring locally in masses several inches across, 
while elsewhere it is present in small quantity only. The larger masses 
seen were extensively altered to limonite. 

Gold occurs in the native state both in the quartz and in pyrite, and 
there may also be a little telluride of gold present since tellurium has been 
detected in the ore. Mr. Knutzen states that the ore seems to be richest 
in gold near the walls of the lenses. The average value of 76% tons of ore 
obtained from these lenses and veinlets was $4.10. Small grains of visible 
gold ranging up to 1 mm. and over in diameter are occasionally seen. 

A piece of quartz, obtained from one of the lenses, contains embedded 
in it a grain of gold, averaging about 0.75 mm. in diameter, which is in 
contact with a minute speck of some soft cleavable mineral with metallic 
luster—probably tetradymite or sylvanite. Only 3 mm. distant from the 
gold, there is a cavity in the quartz, roughly cubical in shape, and about 
1.5 mm. in diameter, which was filled with tetradymite, and in the latter 
a small crystal of pyrite was embedded. Part of the tetradymite was 
removed and tested for identification. It is tin-white in color, has a high 
metallic luster, perfect basal cleavage with flexible laminas, and is quite 
soft, readily marking paper. Heated before the blowpipe it fuses easily 
and gives an orange-yellow sublimate. Upon gently heating with sulphuric 
acid in a test tube the acid assumes the beautiful reddish-violet color dis¬ 
tinctive of tellurium. The same specimen of quartz contains a little 
kaolinized feldspar and some dark brown limonite derived from pyrite. 

A thin section (Spec. 498) from one of the quartz-feldspar veinlets was 
examined under the microscope. The quartz individuals range up to 3 
mm. in diameter, contain numerous irregular gas- and fluid-filled cavities, 
usually arranged in long rows, and show slight wavy extinction, but no 
granulation or other evidence of crushing. The feldspars range up to 


136 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


1 cm. or more in diameter, and are easily distinguished from quartz be¬ 
cause of a slight cloudiness due to partial alteration. Multiple twinning 
after the albite law is sometimes though not always present. The average 
index of refraction is a little less than that of quartz, and this together 
with the extinction angle indicates a composition of approximately Ab 2 An, 
(oligoclase-andesine)/ 1 A little sericite occurs in places, usually in clusters 
of curved and radiating scales. The only other minerals noted in the 
slide were a few grains of ilmenite and its alteration product leucoxene. 

The larger lenses appear to be parallel to the strike and dip of the 
country rock, but many of the veinlets cut directly across. In places, as 
shown in fig. 11, small irregular veinlets and lenses run in every con¬ 
ceivable direction. Where stringers of quartz and feldspar cut across the 
cleavage of the gneiss, smaller veinlets branch off at short intervals and 
run parallel to the schistosity, giving rise to a banded rock which is very 
striking in appearance. 

Specimens of this rock consist of alternating bands of light and dark 
minerals, ranging up to 1.5 cm. in width, which widen here and narrow 
there, and frequently pinch out entirely. Some of the light-colored bands 
are composed essentially of quartz and feldspar, while others consist largely 
of sericite; and the dark-colored bands are composed chiefly of dark green 
hornblende, with sulphides of iron and magnetite abundant in places. The 
quartz-feldspar bands resemble veinlets, and w'hen the rock is fresh it is 
difficult to distinguish between the two component minerals, as they are 
both white. The rock breaks most readily along the sericite bands and 
there presents a light gray surface on which long, narrow, glistening 
streaks of sericite are plentifully sprinkled. These streaks of sericite 
average about 2 mm. in width and range up to 2 or 3 cm. in length. On 
some of the specimens a little light blue cyanite can be distinguished, and 
the sericite streaks are probably due to the alteration of that mineral. The 
dark-colored bands when narrow consist of dark green hornblende with a 
sprinkling of magnetite, but some of the wider bands have a narrow border 
of coarsely crystalline hornblende 2 to 3 mm. wide along their contacts 
with the quartz-feldspar veinlets, while their central portions are filled 
with a fine-grained mixture of carbonate, hornblende, pyrrliotite, pyrite, 
and magnetite. 

a A specimen of this feldspar was submitted to Dr. E. S. Larsen, Jr., for accurate 
determination of the maximum and minimum indices of refraction by the immer¬ 
sion method. His report is as follows: “Oligoelase to andesine. Dominantly 
andesine or oligoclase-andesine. 

(X = 1 . 539 ± 0.003 to 1 . 544 ± 0.003 
y = 1 . 546 ± 0.003 to 1.553 ± 0.003 
Extinction on the rhombic section 12%° andesine.” 



THE GOLD MINES OE THE DISTRICT. 


137 


► N. W. 



SCALE 


0 12 3 Feet 

E- --■ ■■ -- i 

Fig. 11.—Sketch showing distribution of vein quartz, Young American mine. 

The size of the hornblende crystals seems to vary somewhat with 
the width of the veinlets with which they are in contact, and along 
some of the larger veinlets they are 1 cm. in diameter, while pris¬ 
matic crystals of tremolite, which is also present, measure as much as 2 














138 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

cm. in length. Tremolite is frequently abundant near the quartz-feldspar 
stringers, sometimes being roughly segregated into bands, but does not 
appear to be an important constituent in the normal country rock. Occa¬ 
sionally elongated grains of a light brown mineral may be seen, which 
under the microscope were identified as orthorhombic amphibole. 

Microscopic examination of thin sections (Specs. 499, 500, and 501) 
shows that the principal minerals have undergone extensive alteration, 
and it is not always possible to say just how much of this was due to the 
injection of the quartz-feldspar veins and how much is due to weathering. 
The hornblende is pleochroic in shades of light green, blue, and brown, 
and has low interference colors. The tremolite is colorless and shows 
rather high interference colors. In both varieties of amphibole, but espe¬ 
cially in the hornblende, cleavage is well developed; both are ragged in 
outline and frequently show micropoikilitic texture; and each contains 
occasional inclusions of the other. Both show extensive alteration to car¬ 
bonates, and chlorite, probably derived from hornblende, is also present. 
The carbonates in places contain small irregular fragments of amphibole, 
which, on rotating the stage, extinguish together, indicating that they 
belong to a single crystal individual. In addition to the monoclinic 
amphiboles there is a small amount of light yellowish-brown orthorhombic 
amphibole present. It occurs in elongated crystals with poor cleavage and 
ragged outlines which only rarely show straight prismatic boundaries. 
Extinction is parallel to the elongation and the refraction and bire¬ 
fringence are moderate. Quartz occurs in clear irregular anhedra which 
sometimes contain numerous liquid and gas inclusions. The feldspars 
usually show fine albite twinning, and some are also twinned according to 
the perieline law, while others show no visible striations. The index of 
refraction averages about the same or slightly higher than quartz, indicat¬ 
ing that they are chiefly andesine or oligoclase-andesine. Orthoclase is 
rare if present, and has probably been entirely altered to sericite. Some of 
the feldspars show alteration to calcite. Sericite is rare except in light- 
colored bands which are composed almost exclusively of this mineral. It 
occurs in long flakes or scales which usually show good cleavage, and is 
secondary after both cyanite and feldspar. In places a little unaltered 
cyanite can be distinguished in the slides, but it has almost entirely gone 
over to sericite. The iron ores—pyrrhotite, pyrite, and magnetite—are 
plentifully distributed throughout the slide, but are more abundant in the 
areas of dark-colored minerals. The magnetite is frequently idiomorphic, 
and the sulphides in places surround the magnetite. A little biotite, light 


THE GOLD MINES OF THE DISTRICT. 


139 


brown to greenish-brown in color, is occasionally present in small dis¬ 
seminated flakes. 

In the partly decomposed gneiss exposed by the adits, there are 
numerous slickensided surfaces stained black with manganese, probably in 
the form of wad. Some of these surfaces are very large, covering an area 
of at least several square yards. As a rule they conform in strike and dip 
to the schistosity of the formation, and they are common along the walls 
of the quartz veins. Similar slickensided surfaces occur in the workings 
on the “Sulphur” vein, but they were not found in the lower openings 
where the rock is unaltered by weathering. Because of their localization 
in the weathered material it is believed that these slickensides are due to 
changes in volume resulting from decomposition. 

The Belzoro Mine. 

Location .—The Belzoro mine, consisting of about 374 acres, is located 
6 miles northeast of Columbia and three-quarters of a mile north of 
Lantana. The veins on this tract evidently belong to the same system as 
the “House” vein on the property of the Young American mine (see pp. 
134-139), which adjoins the Belzoro on the northeast. 

History. —Mr. Hamilton states that “the antiquity of the Belzoro mine 
is evident from the fact that crucibles, made by the Indians, or perhaps 
some remoter and unknown tribes, have been found on it, bearing a rude 
resemblance to an acorn cup, and manifestly devoted to the use of melting 
the precious metals,”® but in this belief he is probably mistaken. Ho 
articles of Indian manufacture made from gold have been found in Vir¬ 
ginia, and students of the North American Indian are generally agreed 
that he was ignorant of the art of melting metals. The so-called crucibles 
were probably used for some other purpose and doubtless were brought 
from the Indian soapstone quarries 3 miles northeast of this property, 
which are described on pages 170-171. 

Gold was discovered on the Belzoro tract by surface washing in 1832, 
at which time the property belonged to Mr. William Southworth. The 
placer gravels are said to have been very productive, $30,000 having been 
recovered from a limited section known as “Dry Gulch.” fi Bed rock was 
1 to 6 feet below the surface and many nuggets weighing from 4 to 7 penny¬ 
weights were found. 0 The work of washing gold from the gravels con- 

aHamilton, J. R., The Natural Wealth of Virginia, Harper’s Magazine, 1865, 
vol. xxxii, pp. 32-42. 

&Snell, P. A., From a report on the Belzora mine. 

^Hamilton, J. R., Op. cit. 



140 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


tinned with varying success up to 1849, when the property was sold to 
Mr. Geo. Fisher. 

Several shafts were sunk to depths 30 to 60 feet and many surface 
cuts and pits were opened. A 10-stamp mill was built to treat the ores 
which are said to have yielded as high as $300.00 per day, but all mining 
operations were interrupted by the Civil War. After the close of the war 
a little work was done from time to time, but the mine has remained idle 
since the mill burned some years ago. 

Descriptive geology .—There are no outcrops on the property and very 
little float rock aside from vein quartz can be found. The old workings 
have caved and are now inaccessible, but information obtained elsewhere 
in the vicinity confirms the data collected on the property and indicates 
that the country rock consists of a series of quartzose gneisses and schists 
varying somewhat in composition. A number of large pieces of float were 
found near the branch where it is crossed by the road a short distance 
northeast of the house. This rock is a light gray, slightly banded gneiss 
composed for the most part of quartz, white mica and feldspar, with a little 
dark mica and magnetite. A detailed petrographic description is given 
on page 39. While the rock was not found in place at this point it does 
outcrop beyond the limits of the property in both directions along the strike 
and is probably the dominant rock type in this vicinity. The ferruginous 
quartzite found on the Webb place (see pp. 19-20) also continues on this 
property. The veins are said to be enclosed in light-colored quartz-sericite 
schists (the talcose slate described by some of the early writers). 

According to P. A. Snell there are two well-defined veins on the 
property 300 yards apart, one averaging from 2 to 3 feet in width, and 
the other from 3 to 4 feet, while the course of both is northeast and south¬ 
west and the dip 45° toward the southeast, approximately parallel to the 
strike of the country rock. The two principal veins are paralleled by a large 
number of flat lens-like ore-bodies varying from 1 to 6 inches in width 
which are not continuous for any great distance, but pinch out and start 
in again a little to one side or farther along the strike.® 

The ore is described as quartz carrying iron pvrite which is largely 
oxidized near the surface, and on either side of the veins there is said to 
be a narrow selvage of clay and grit (probably kaolin from the decomposi¬ 
tion of feldspar), which is quite rich in gold, the latter showing plainly 

aSnell, P. A., Op. cit. 

Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1S68, vol. vi, p. 393. 



THE GOLD MINES OF THE DISTRICT. 


141 


on panning a little of the material. This description indicates a type of 
ore-deposit similar to the lenses that parallel the “House” vein on the 
property of the Young American mine described in detail on pages 134-139. 

These small lenses were worked entirely by open cuts and the ore 
obtained was washed through sluices or rockers to separate the free gold 
in the soft material (kaolin), which varied in value from $2 to $20 per 
ton. After the fine material was washed away the balance consisting of 
coarse quartz was put through the mill to recover the gold that it contained. 

Production. —Mr. Snell believes that about 2,000 to 2,500 tons of ore 
have been milled, this being derived mostly from the two principal veins 
but partly from the open cuts on the small lenticular ore-bodies. The 
property is estimated to have produced from placer gravels and from veins 
a total of not less than $100,000.® 

The Collins Mine. 

The Collins mine is situated on the east side of the Belzoro property 
1 mile northeast of Lantana. It was probably the first mine worked for 
gold in this district if not in Virginia. Gold was first found in the branch 
crossing the property, and while the exact date of the discovery is not 
known, it must have been prior to 1830. The Fishers made preparations 
to work the gravels, building dams across the branch and installing rockers, 
but before operations were actually under way they turned the property 
over to Steven Collins and began work on the Busby branch instead. Mr. 
Collins washed the branch gravels successfully for several years, and later 
gold-bearing gravels were found 30 or 40 feet above the branch on the 
north side. Sluice ways were cut from the bottom of the hill and the 
gravel worked by hydraulic mining. Little if any vein-mining was ever 
conducted on the property. 

In addition to the mines described above gold has been reported on a 
number of properties in the vicinity of Lantana, and a little prospecting 
has been done at several places, chiefly for placer gold. On a property 
lying south of the Belzoro mine and formerly known as the Marks mine, 
surface washing was commenced in 1830 by Woodfork and continued for 
some time by various owners. Other placer mines which have been 
operated at various times in this neighborhood were known as the Eades, 
Big Bird, and Laury mines. 

The Morgan Mine. 

The Morgan mine is located just west of the property belonging to the 
Young American mine. The placer gravels on this place were early 


«Snell, P. A., Op. cit. 



142 GEOLOGY OF THE GOLD BELT IN THE JAMES BIYER BASIN. 

worked for gold and later some vein mining was done. According to 
Credner the main vein is 4 feet wide and a smaller parallel vein in the 
hanging wall was also worked. Before the war, ore was hauled to the 
Belzoro mill and is said to have yielded 70 pennyweights of gold per day, or 
about $3,000 in eight months.® Later a 10-stamp mill was built but the 
size of the tailings pile indicates that little ore was milled. At present 
nothing remains of the mill and the old shafts and pits are completely 
caved. 

The Grannison Mine. 

The Grannison mine is situated on the west side of Camp Branch, a 
mile northwest of Lantana and a mile south of Caledonia. The placer 
gravels were extensively and successfully worked during the period that 
preceded the Civil War, and 3 quartz veins were opened up. One of these 
was worked to some extent by open pits and a shaft 42 feet deep. After 
the war the veins were reopened and a 10-stamp mill built near the branch, 
but at present the mill is in ruins and all of the old workings caved. Most 
of the work seems to have been done a short distance northeast of the mill 
where there is a series of old shafts and pits extending for about 150 yards 
in a direction NT. 45° E. There are several pits located a quarter of a mile 
north, said to have been opened on a smaller vein which was very rich. 

Atmore, Kent, and Other Properties. 

On the Atmore and Kent properties, lying southwest of the Grannison 
mine, several veins have been explored and a little mining done, but all 
of the work has been of a superficial nature. Small veins have been pros¬ 
pected on a number of other places in this vicinity, but aside from placer 
washing practically no mining has been attempted. Nearly all the gravels 
along Camp Branch and some of the smaller branches that enter it have 
been washed for gold. 

The Bertha and Edith Mine. 

Location .—The Bertha and Edith mine is situated on the east side of 
Big Byrd Creek in Goochland County, 3 miles northeast of Columbia. 

History .—The placer gravels along the branches were first worked prior 
to the Civil War, and the Maple and Camp branches which flow through 
the property are said to have yielded much gold. In 1877, the Bertha 
and Edith Gold Mining Company bought the mineral rights and began 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, pp. 26-27. 



THE GOLD MINES OF THE DISTRICT. 


143 


development work on the quartz veins. A little later a Fraser and 
Chalmers 20-stamp mill was erected to crush the ore and recover the gold. 
In 1882, the Tagus Mining and Milling Company, which was operating the 
Gilmer (Young American) mine, 4 miles northeast, obtained a lease and 
option on the property and began work. During this lease some hydraulic 
mining was carried on, water being furnished under pressure by a large 
pump and the gravel washed through sluice boxes. Several veins were 
prospected by surface openings but most of the underground development 
was limited to the “Oak Hill” and “Maple Branch” veins. The “Oak Hill” 
vein was explored by an adit 400 feet long, which drained the hill 75 feet 
below the summit and was connected with an upper level on which there 
were 300 feet of drives and cross-cuts.® The “Maple Branch” vein was 
explored by a tunnel, but work had to be stopped on account of bad ground. 

In 1897, the Rivanna Gold Mining Company reopened the “Oak Hill” 
vein and built a cyanide plant to treat the tailings from the stamp mill. 
Milling had scarcely begun before the whole plant was destroyed by fire 
in 1898, and since that date no work has been carried on. While the “Oak 
Hill” vein was being reopened the company prospected the placer gravels 
in the flat near the mouth of Camp Branch and started to work the deposits, 
the method being to first remove the overburden with scrapers and then 
wash the gravel in rockers, but this was discontinued when the mill burned. 
At the present time the shafts are partly caved and all the underground 
workings are inaccessible. 

Description of veins and country rock .—The country rock in which the 
veins are located consists chiefly of schists and gneisses of sedimentary 
origin, and their contact with hornblendic border facies of the granite is 
only about half a mile southeast of the “Oak Hill” vein. The dominant 
rock in the sedimentary series is a medium-grained gneiss composed essen¬ 
tially of quartz, sericite, and feldspar in the order named, with a little 
biotite and a few grains of magnetite. This is the only rock outcropping 
on the property excepting along the bluffs that border Big Byrd Creek 
where quartz-sericite schists and hornblende schists occur in places. 

The “Oak Hill” vein varies up to 6 feet in width and is said to have 
averaged about 3 feet. Ore found on the dump consists of ordinary vein 
quartz containing considerable fine-grained pyrite, which is partly oxidized 
to limonite, and on crushing and panning it shows fine grains and scales 
of free gold. Some of the pieces show a little white mica and kaolin un- 

aHotchkiss, Jed., Virginia Minerals for the New Orleans Exposition, The Vir¬ 
ginias, 1884, vol. v, p. 166. 



144 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


doubteclly derived from feldspar. A little magnetite is occasionally present. 
The ore from this vein is said to have averaged a little over $5.00 per ton. 
The “Maple Branch” vein has a northeast-southwest strike and is said to 
be much narrower but richer in gold than the “Oak Hill" vein. Miners, 
who worked on the property when the openings were made, state that this 
vein carried a large amount of white kaolin. The “House” vein, situated 
about a quarter of a mile northwest of the other two, has been worked to 
a limited extent, but nothing definite could be learned concerning it. 
Float rock picked up on the surface assayed as much as $32.75 per ton. 
There are some placer gravels remaining on the property that have never 
been worked (see pages 239-240). 

The Pryor Tract. 

The Pryor property is located IV 2 miles southeast of Tabscott and lies 
south of the Busby mine. The placer gravels along Busby Branch, which 
crosses this property, were worked soon after the first discovery of gold in 
the district. Becently several small shafts have been sunk on the property 
in the hope of locating the “Waller” vein, but, so far as is known, nothing 
of value was found. 

The Moss Mine. 

Location .—The Moss mine is located on the south side of the Columbia- 
Tabscott road, about 8 miles northeast of Columbia and 1^2 miles south¬ 
west of Tabscott. 

History .—The Moss vein, on which most of the work has been done, is 
said to have been discovered in 1835 by John Moss.® Prof. Silliman, 6 
reporting on the property in 1836, found the mine developed by two incline 
shafts sunk on the vein; one measuring 31 feet along the slant and having 
a vertical depth of 25 feet, while the other was 50 feet deep, though the 
lower 20 feet was inaccessible at the time of his visit. The two shafts 
were connected by an adit 70 feet in length and the vein was exposed 
throughout the length of these workings. Measurements taken at intervals 
along the vein ranged from 16 to 30 inches in width and averaged about 
24 inches. The inclination, about 45° toward the southeast, and the strike, 
about north by east and south by west, were conformable with the strati¬ 
fication of the inclosing slaty rocks. A sample was taken by knocking off 
pieces of ore at intervals of 12 feet along the vein and this, after being 

«Nitze, H. B. C., and Wilkins, H. A. J., Gold Mining in North Carolina and 
Adjacent South Appalachian Regions, Bull. 10, N. C. Geol. Survey, 1897, p. 75. 

fcSilliman, B., Remarks on Some of the Gold Mines and on Parts of the Gold 
Region of Virginia, Amer. Jour. Sci., 1837, vol. xxxii, pp. 98-130. 



THE GOLD MIXES OF THE DISTRICT. 


145 


broken down and subdivided to give a final sample of 9 pounds, was washed 
and amalgamated; the button of gold recovered in this manner weighed 
11 grains, giving the ore a value of about $105 per ton. In another trial 
Prof. Silliman obtained 6 grains of gold from 3 y 2 pounds of powdered 
rock in which no gold was visible, and in a third experiment two pounds 
of ore yielded 5 grains of gold. 

Credner states that the Moss mine was worked from 1836 to 1838 by a 
company (The Richmond Mining Co.) whose shares rose in a year’s time 
from $5 to $300, but fell as quickly to nothing.® 

The mine was reopened in 1891 and tests made on the ore with a 
3-stamp prospecting mill, 6 and during 1904 the property was operated 
under lease by the Telluric Gold Mining Company.® At this time the 
mine was developed by 2 main shafts, known as No. 1 and No. 2. The 
No. 1 shaft was sunk on an incline to a depth of 118 feet, and levels run 
east and west a total distance of 285 feet in ore milling $15 per ton. In 
the west level a small shoot was encountered which averaged $150 per ton 
in gold, and 40 ounces in silver. The No. 2 shaft was carried to a depth 
of 130 feet and levels driven 60 feet east and west along the vein, the ore 
developed milling $14.40 per ton. A 3-stamp battery was added, giving 
the mill a total of 6 stamps. Regular assays of tailings indicated an 
average of $2.00 per ton. 

Descriptive geology .—The vein is said to consist of laminated quartz 
lying in more or less lenticular masses between walls of micaceous slate. 
Pieces of the ore examined by the writer are in the form of thin plates 0.5 
to 1 inch thick, and broken along joint planes spaced 5 to 9 inches apart. 
Coarse gold, in grains about 0.5 mm. in diameter, is sprinkled along the 
surfaces of the laminae, a little pyrite mostly altered to limonite is present, 
while flakes of white mica and considerable kaolin, probably derived from 
feldspar, were also noted. Black tourmaline is said to have been common 
in some of the ore and prisms of this mineral were found in a number of 
pieces of float on the surface. 

Specimens found on the shaft dumps indicate that the wall rock is a dark 
gray schist with slaty cleavage, composed for the most part of fine-grained 
quartz and biotite, varying somewhat in their relative proportions but with 
the quartz always largely in excess. A few small black needle-like prisms 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 27. 

&Eng. and Mng. Jour., 1901, vol. lii, p. 108. 

cFroehling and Robertson, A Hand-Book on the Minerals and Mineral Resources 
of Virginia, 1904, pp. 51-52. 



146 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

of tourmaline or hornblende are also present. The soft running ground 
which is reported to have given much trouble in shaft sinking, was probably 
due to disintegrated schist of this character saturated with water. 

Pieces of hornblende schist were also found on one of the dumps. This 
is a greenish-grav, medium-grained rock composed of dark green horn¬ 
blende in crystals ranging up to 2 or 3 mm. in diameter, fine-grained, 
white quartz and feldspar, and numerous pink garnets, usually less than 
1 mm. in diameter. In thin section under the microscope the hornblende 
is light green in color, very ragged in outline, and micropoikilitic from 
numerous inclusions of quartz and feldspar. Quartz, the second mineral 
in relative abundance, frequently contains inclusions of broken zircons, and 
gas- and liquid-filled cavities. The feldspar is plagioclase, probably 
andesine, and in places shows albite twinning though this is usually absent. 
The large, light pink garnets which are plentiful in the slide are often 
ragged in outline and contain many included quartz grains. Chlorite, 
partly derived from garnet but mostly from the hornblende, is present in 
light green flakes. A very little biotite, scattered grains of magnetite, and 
some pyrite, partly altered to limonite, make up the minor accessories. 
In the absence of a chemical analysis or data bearing on the structural 
relations of this rock it is impossible to state whether it is igneous or sedi¬ 
mentary in origin, but the writer is inclined to the latter alternative. 

An old shaft, partly caved, which is located close to the county road is 
said to have been sunk to cut the Hodges vein. Partly decomposed garnet- 
iferous mica schist is exposed on the dump. 

The Busby Mine. 

The Busby mine lies 8% miles northeast of Columbia and 1 mile 
southwest of Tabscott, joining with both the Moss and Bowles properties. 
It was one of the first gold mines in the State to be worked, the placer 
gravels on Busby Branch having been washed by the Fishers as early as 
1829 or 1830. In working up the branch, the Busby vein was discovered, 
and then a small wooden stamp mill run by horse-power was put up by 
the Fishers and D. W. K. Bowles. 

In 1836, when Prof. Silliman 0 visited the district to report on the 
Moss and Busby mines, they were being developed by the Kichmond 
Mining Company. A shaft had been sunk to a depth of 57 feet with the 

aSilliman, B., Remarks on Some of the Gold Mines, and on Parts of the Gold 
Region of Virginia, founded on personal observations made in the months of August 
and September, 1836, Amer. Jour. Sci., 1837, vol. xxxii, pp. 98-130. 



THE GOLD MIXES OF THE DISTRICT. 


147 


expectation of striking the vein at 70 feet, the vein having first been 
proved by 4 prospecting pits 20 to 26 feet in depth. These openings showed 
the vein to be from 12 to 30 inches wide, averaging 15 to 18 inches. The 
vein quartz, as described by Prof. Silliman, has a coarsely granular texture 
with a strong resemblance to coarse lump sugar, much of it being white 
and apparently free from all foreign matter other than the inherent gold. 
A 6-pound sample picked at random from a large pile was crushed, washed, 
and the gold amalgamated with mercury; upon retorting it yielded 6 
grains of gold worth 4% 2 cents per grain. This is equivalent to over $81 
per ton. A picked sample containing small points of visible metallic gold, 
when treated in the same way, yielded 6 grains of gold from 2 pounds of 
ore, or about $250 per ton. 

Notwithstanding the reported value of the ore, comparatively little 
mining'seems to have been carried out on the property, and when it was 
visited by Credner in 1865 the mill was in ruins.® He states that the 
continuation of the Moss vein was exposed by 4 shafts the first and last 
of which were one mile apart. 

"When visited by the writer in 1910 the shafts had caved so that few 
observations could be made. Several old pits are located about 50 yards 
north of the Columbia-Tabscott road and in line of strike with the 
Tellurium vein system. On the dump of one of these openings pieces of 
quartzite were found identical in appearance with the material from the 
“Big Sandstone” vein, but whether it has been mineralized at this point 
or not, could not be determined. About 100 yards south of the road a 
small pit had been sunk, apparently on a ferruginous quartzite similar to 
that known as the “Hodges” vein at the Scotia mine. 

The Payne Tract. 

The Payne tract is located on the south side of the county road half a 
mile southeast of Tabscott. It adjoins the Busby mine and was formerly 
a part of that property. There are a number of old surface cuts and caved 
shafts which extend in a line running about N. 58° E. A large pile of mill 
tailings a short distance below the openings indicates the site of the old 
mill of which no other trace remains. The mill that Credner found in 
ruins when he visited the Busby mine was probably located at this point. 
In 1911 an attempt was being made to reopen one of the old shafts. 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Anier. Jour, of Mng., 1S69, vol. vii, p. 27. 



148 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


The Waller Mine. 

Location .—The Waller mine is situated in Goochland County half a 
mile southeast of Tabscott and about 10 miles northeast of Columbia, the 
nearest railroad station. 

History .—The Waller mine was discovered in 1831, and during that 
year Cole and Woolfork carried on surface washings for several months. 
Veins were discovered by Moss in 1832, and a vein 6 feet thick is said to 
have been opened by the Fishers and worked until the land was purchased 
by Wm. K. Smith. Later it was sold to Richards, of New York, who 
worked the mine 12 months and then sold it to an English company for 
a large sum. After two years, during which it is said to have been badly 
managed, the property was divided and sold in two parts. Since that 
time only the western part of the old estate has been known as the V aller 
mine. In 1865, Turner, Hughes & Co. sank a shaft and did some develop¬ 
ment work, but since that date nothing has been done, aside from 30 days’ 
work in 1876, until the present company began operations in 1910.® During 
the latter year a shaft was sunk to a depth of 72 feet and two cross-cuts 
driven northwest at depths of 45 and 60 feet, respectively. A small vein, 
said to be the Waller vein, was encountered in the 60-foot cross-cut, but 
the drive which was started southeast along the vein soon ran into old 
workings. Another shaft was started in 1911 to strike the vein at greater 
depth, but when the property was visited in the summer of that year the 
vein had not been reached. A small mill is said to have been operated 
on the property in the early days but no trace of it remains to-day. Before 
the property was divided, veins belonging to the Tellurium system which 
crossed the northwestern portion of the property were also developed to 
some extent. 

Descriptive geology .—The mine is situated in an area of schists and 
quartzites not far from their contact with the hornblendic border facies 
of the granite, which is found outcropping a short distance southwest of 
the property. Because of lack of exposures it is not possible to accurately 
locate the contact at this point, but many pieces of hornblende schist were 
found on the surface within less than 200 yards southwest of the vein. 
About a quarter of a mile northeast of the vein a small pit was sunk in 
prospecting for iron. The material encountered seems to have been a 
ferruginous quartzite similar to that found elsewhere in the district. 
About half a mile northwest of the mine occurs the same series of quartzites 
and schists found at the Tellurium mine. 

®Most of the facts stated above were taken from “The Natural Wealth of 
Virginia,” by J. R. Hamilton, Harper’s Magazine, 1865, vol. xxxii, pp. 32-42. 



THE GOLD MINES OF THE DISTRICT. 


149 


The strike of the Waller vein at the surface, as indicated by the old 
open cuts and caved stopes which extend for about 300 yards along the 
outcrop, is X. 58° E. When the mine was examined by the writer, the 
vein was exposed for a distance of only 25 feet along the strike at a depth 
of 60 feet below the surface. At this point the dip was about 40° toward 
the southeast and the strike N. 60° E. The width of the vein where it 
could be measured ranged from 4 inches down to less than an inch, and 
was composed for the most part of quartz, feldspar, more or less kaolinized, 
and a little limonite resulting from the alteration of pyrite. The relative 
proportions of these constituents varied greatly; where widest the vein 
consisted almost entirely of white vitreous quartz, but in most places 
feldspar was abundant, and in some of the narrower portions was dominant. 
The limonite was commonly mixed with kaolin and quartz to give an 
earthy, yellowish-brown material, which often contained much coarse gold. 

The textural relations of the quartz and feldspar are similar to those 
of a typical pegmatite and in places there is a suggestion of graphic inter- 
growths. The feldspar individuals range up to 1 cm. or more in diameter, 
and in the wider portions of the vein are more or less concentrated near 
the walls. The gold when visible occurs in irregular grains and rough 
wire-like masses, some of which measures 3 mm. in length, and is usually 
associated with decomposed earthy material heavily stained with limonite. 
Specks of gold may occasionally be seen in feldspar and clear, unstained 
quartz, and more rarely in the wall rock close to the vein. 

Microscopic examination of the vein rock in thin section (Spec. 217) 
shows no accessory minerals other than a little sericite derived from the 
feldspars. The quartz is nearly free from optical distortion and contains 
numerous gas- and liquid-filled cavities. These cavities occur partly in 
irregular branching and interlaced forms, and partly in smaller spherical 
and elliptical shapes which are usually grouped in rows and planes. In 
places the inclusions are so small and plentiful as to give the quartz a 
clouded appearance even under a magnification of 200 diameters. The 
feldspars are extensively kaolinized and show some alteration to sericite, 
but apparently consist entirely of acid plagioclase (albire-oligoclase to 
oligoclase).® Twinning after the albite law is common, though much of 

«Dr. E. S. Larsen, Jr., using the immersion method, determined these feldspars 
to be albite-oligoclase to oligoclase and states that the fresher crystals appear to 
be oligoclase. The indices of refraction as determined by him are: 

'i = 1 . 535 ± 0.003 to 1 . 538 ± 0.003 
Y 1 = 1 . 543 ± 0.003 to 1.547 ± 0.003 


6 



150 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

the feldspar is unstriated. A photomicrograph of some of the striated 
feldspar is shown in PL VIII, fig. 2. The narrow veinlet crossing the 
feldspar is composed of quartz. 

The wall rock is fine-grained and badly decomposed, so that it is very 
difficult to obtain specimens fresh enough for identification. The rock 
exposed on the hanging wall side of the vein is dark blue in color and 
consists essentially of quartz and magnetite in grains that are too small 
for sight determination. For a distance of 3 feet or more from the vein 
there are numerous veinlets composed of quartz and feldspar, which range 
from an inch or more in thickness down to threads and lenses microscopic 
in size, and which are approximately parallel to the main vein. Limonite 
and iron-stained cavities due to the oxidation of pyrite occur in places, 
and there is probably some gold, for these veinlets appear to be essentially 
the same as the vein in which gold was identified. Small flakes of biotite 
usually occur along the contact between the veinlets and the country rock, 
and the mica is plentiful along both walls of the principal vein. The rock 
on the foot-wall side was not as well exposed. Where it could be examined 
it was much weathered, hut appeared to consist of biotite, kaolinized 
feldspar, and quartz. Pieces of rock from the hanging wall sometimes 
contain small, light brown crystals, often radiating, which resemble silli- 
manite, but are too small and too much decomposed for positive identifi¬ 
cation. 

A thin section (Spec. 219) of the hanging wall rock was also examined 
under the microscope. It is schistose in structure and consists of a fine¬ 
grained ground-mass of quartz, magnetite, and a little feldspar, in which 
there are numerous small irregular lenses and veinlets composed of coarser 
grained quartz and feldspar. The quartz grains in the ground-mass show 
wavy extinction, the magnetite is present in idiomorphic grains, and the 
feldspar, which seems to be chiefly acid plagioclase, is more or less 
kaolinized. The quartz in the lenses shows no optical distortion, and fre¬ 
quently contains numerous small fluid-filled cavities. Many of these 
cavities contain rapidly vibrating bubbles. A little zircon and titanite are 
also present as inclusions in the quartz. Feldspar is not very plentiful, 
and is chiefly concentrated along the border portions and at points where 
the lenses pinch out. Most of the feldspar crystals show Carlsbad twinning 
and are probably orthoclase, hut a little acid plagioclase is also present. 


THE GOLD MINES OF THE DISTRICT. 


151 


On the surface near one of the old openings pieces of vein rock were 
found which consist of intercrystallized quartz and calcite. The calcite 
is coarsely crystalline, has curved cleavage surfaces, and contains much 
iron and a little magnesium. Dark green hornblende partly altered to 
chlorite and a little pyrrhotite are also present in the calcite and along its 
margins. Other pieces of rock on the old dump have a banded structure 
and are composed of alternating layers in which the dominant minerals 
are, respectively, coarsely crystalline, dark green hornblende and white 
finer-grained calcite. Lenses of quartz occur in places and there is a little 
pyrrhotite and some pvrite present. 

The Fleming Mine. 

Location .—The Fleming mine is situated in Goochland County about a 
mile northeast of Tabscott and on the southeast side of the county road. 

History and description .—The placer gravels on this property are said 
to have been washed during the early days of gold mining in the district. 
Underground work was started by General Cook in 1846 and a 6-stamp 
mill operated by him is said to have yielded on occasions as much as $200 
per day. This success, however, was short-lived as the vein was soon lost. 
At this time two shafts were sunk to depths of 60 and 35 feet, respectively. 
During its early history the property was known as Hodge’s mine, but in 
1848 it was sold to the L’Aigle d’Or Company of Xew York.® Little 
development work was attempted until after the Civil War, when the mine 
was reopened by several small shafts, and since that time it has been known 
as the Fleming mine. 

When the property was visited in 1910 all of the openings were in¬ 
accessible; a series of old pits and shafts was seen extending in a direction 
N. 60° E. for about 150 yards, and in one of the shafts decomposed schists 
were exposed having a strike of N. 61° E. and a dip of 45° toward the 
southeast. A few pieces of vein quartz were found on the’ dump, but they 
showed little evidence of mineralization. 

Shannon Hill. 

Shannon Hill is the most northeasterly point within the area where 
gold has been found. Some prospecting was carried on here years ago, 

"Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 26. 



152 


GEOLOGY OF THE GOLD BELT IN THE JAMES LIVER BASIN. 


but nothing further seems to have been clone. Credner examined the 
property in 1865 and states that a lode, 1 to 3 feet wide and paralleled 
by two smaller veins, was exposed by surface pits. The strike is given 
as N. N. E. and the dip 40° to the east. The veins are said to consist 
of white translucent tabular quartz with a great deal of earthy oxide 
of iron and some gold. Garnetiferous mica schist outcrops in the road at 
Shannon Hill, having a strike of N". 45° E. and a dip of about 45° south¬ 
east. While considerably decomposed it is apparently similar to the wall 
rock at the Tellurium mine and probably represents the same formation. 
Placer gravels were washed on this property before the Civil War and 
considerable gold is said to have been recovered. 


The Benton Mine. 

Location .—The Benton mine is located in Goochland County about 
three-quarters of a mile northeast of Tabscott and on the northwest side of 
the county road. 

Description .—This property was explored by a shaft, now inaccessible, 
and the size of the clump indicates that it reached a considerable depth. 
The country rock found on the dump is a garnetiferous schist similar to 
the wall rock at the Tellurium mine, and pieces of vein quartz were seen 
that contained a little kaolinized feldspar and some white mica. The 
property is in direct line of strike with the Tellurium system of veins, and 
this fact together with the material found on the dump indicates that the 
vein is similar in its general characteristics to those described under that 
mine. There is a number of old pits and caved shafts between this point 
and Tabscott, which were probably sunk in prospecting the same vein or 
others belonging to this system, but the openings are so old that the 
material on the dumps has completely disintegrated, and therefore no 
definite information could be obtained concerning the exposures. A few 
pieces of massive diorite, evidently derived from some dike, were found on 
the surface. The rock is described in detail on page 85. 

The Tellurium Mine. 

Location .—The Tellurium mine, located r H 1 / 2 miles northeast of 
Columbia and 214 miles southwest of Tabscott, lies partly in Fluvanna 
and partly in Goochland counties. 


THE GOLD MINES OF THE DISTRICT. 


153 


History and description .—It was one of the first properties in Virginia 
on which vein mining for gold was attempted, and its history differs from 
that of most mines in this section in that the veins were discovered and 
worked before the placer gravels. The first discovery on the place was 
made in 1832 by G. IV. Fisher while hunting, and in 1834 the property 
was leased from its owner, Mr. Hughes, by Geo. Fisher, his two sons, 
G. IV. and J. A. Fisher, and Judge D. W. K. Bowles. 

At first the ore was raised and crushed by hand, and the gold separated 
from its gangue by washing in a box. The crushing was carried on in 
wooden mortars lined with iron, the heavy pestles being attached to sweeps 
which were likewise operated by hand. Later an arrastra driven by horse¬ 
power was installed, and finally a small stamp mill was built on the branch 
about one mile below the mine. This was probably the first stamp mill, 
or “pounding mill” as they were originally called, to be erected in this 
country, and it is supposed that the innovation was derived from Europe. 
According to Nitze and Wilkins,® a 6-stamp mill was in operation at the 
Tellurium mine as early as 1836. The ore was crushed on an iron die 
plate by 50-pound wooden stamps with iron shoes; the stamp stems were 
square and did not revolve as in later mills, for the cams worked in slots 
cut into the stems. 

The mine was in continuous and profitable operation for 14 years 
under the Fisher-Bowles lease, and during that period the work was con¬ 
fined to the “Little” and “Middle” veins which are said to have been the 
richest, but very little authentic information regarding the production or 
the value and character of the ore is obtainable at this date. The “Little” 
vein is said to have averaged less than a foot in width and the deepest 
workings were only 65 feet, though as a rule the vein pinched out before 
this depth was reached. According to G. IV. Fisher 100 pounds by weight 
of the richest ore ever obtained from this vein, on crushing and washing, 
yielded 210 pennyweight of gold. 6 The “Middle” vein is said to have 
averaged iy 2 to 2 feet in width but the ore was not so rich as the “Little” 
vein. 

Dr. Gray, in a letter to Dr. Thomas Pollard, gives the average value of 
the ore obtained from the two veins during this 14-year period as $100 per 
ton.® Prof. B. Silliman visited “Fisher’s or Hughes’ mine,” as the property 

«Nitze, H. B. C., and Wilkins, H. A. J., Gold Mining in North Carolina and 
Adjacent South Appalachian Regions, Bull. 10, N. C. Geol. Survey, 1897, p. 35. 

^Statement made to the writer by R. H. Fisher, nephew of G. W. Fisher. 

cHotclikiss, Jed., The Tellurium Mine and Virginia Gold Mining, The Virginias, 
1881, vol. ii, p. 85. 

Pollard. Thomas, The Gold Belt of Virginia in “Gold, Its Occurrence and 
Extraction,” by A. G. Locke, New York, 1882, pp. 182-190. 



154 GEOLOGY OF THE GOLD BELT IN THE JAMES EIVER BASIN. 

was variously called at that time, in 1837, and quotes Mr. Fisher as saying, 
that the average value of the ore w T as $3.15 for every 100 pounds, while 
the cost did not exceed 30 to 35 cents per hundred pounds.® According 
to local report, the lessees paid a royalty of 10 per cent, of the gold re¬ 
covered, and during the period of the lease Mr. Hughes received as his 
share $13,000 or $15,000, the accounts differing as to the exact amount, 
making a total production of $130,000 or $150,000. 

In 1848, the property was bought by Commodore E. F. Stockton, who 
erected a 40-stamp mill and proceeded to work the mine on a larger scale. 
His operations extended over a period of about 9 years, and then the mill 
was burned to the ground. The “Middle” and “Little” veins were worked 
to a limited extent, but most of the mining was confined to the so-called 
“Big Sandstone” vein, which averaged about 3 feet in width and in places 
reached 6 feet or more. The deepest shaft was sunk in the hanging wall 
about 300 feet from the outcrop and is reported to have reached a depth 
of 136 feet, but the other openings would not average 45 feet, and practi¬ 
cally all of the ore came from above the water level. Starting from a small 
branch that crosses the outcrop, a tunnel was driven along the vein, and 
nearly all the stoping was above this level. These old workings are now 
mostly caved, but they can be traced across the property on the surface 
for a distance of about 1,500 feet along the strike. 

Many remarkable tales cluster about the name of Commodore Stockton 
and the fortunes said to have been made by him in Virginia gold mines, 
but few of these can be verified. Estimates of the gold extracted by him 
from the Tellurium veins vary from $75,000 to over $1,000,000, but the 
lower figure is probably more nearly correct. 

After the mill had burned the property was sold and no further work 
was carried on until after the war. Since that time there have been 
spasmodic attempts to reopen the mine, but none seem to have been 
attended with any great degree of success. About the year 1880, a 10- 
stamp mill with amalgamated copper plates was built, and for a short 
time the mine was operated under lease. Most of the ore mined at this 
time was taken from the “Big Sandstone” vein. A few years later the 
stamp mill was pulled down and replaced by some kind of a revolving mill, 
which was used to treat ores from the “Gold Hill” veins on the Bowles 
tract, adjoining the Tellurium on the northeast. About the year 1890, two 
Tremain steam stamps were installed on the property, but they were never 
used to any extent. 

aSilliman, B., Remarks on Some of the Gold Mines, and on Parts of the Gold 
Region of Virginia, Amer. Jour. Sci., vol. xxxii, pp. 98-130. 



THE GOLD MINES OF THE DISTRICT. 


155 


The last work done on the property was in 1909-1910, when the Argus 
Gold Mining Corporation cleaned out part of the old workings on the 
“Big Sandstone” and “Middle” veins, and sank a 3-compartment incline 
shaft on the “Big Sandstone” to a depth of about 90 feet measured along 
the dip. Drives were started in either direction along the strike of the 
vein, but had only progressed a few feet when the mine was closed down. 
One of the old Tremain stamps was set up again and used in testing a few 
tons of ore from the “Middle” and “Big Sandstone” veins. 

Present underground development. —When the property was examined 
by the writer in the summer of 1910, the “Big Sandstone” vein was exposed 
by the new 90-foot incline with short drives at the bottom, and by an old 
drain tunnel which had been reopened for a distance of 90 yards along the 
vein, and which connected with a shallow incline. The “Middle” vein was 
exposed by an incline shaft 50 feet deep and about 125 feet of drives along 
the vein, all above water level. A little stoping had been done on the latter 
vein. While there has been a number of other shafts and openings made 
at various times, they are not now accessible. 

The Tellurium Vein System. 

Introduction. —The geological descriptions given below will suffice for 
all properties located along the line of the Tellurium vein system, and 
under each mine only such details will be referred to as are not 
mentioned in the description of the system as a whole. The Tellurium 
system of veins has been developed almost continuously for a distance 
of a mile, and prospected at short intervals for 5 miles or more along its 
line of strike. The greatest amount of development work, however, has 
been done at the Tellurium and Bowles mines. The only openings 
accessible, when the area was studied by the writer, were located on the 
adjoining properties of the Tellurium and Scotia mines; and therefore 
the detailed geological descriptions will be limited to these two properties; 
but everything that could be learned concerning development work done 
elsewhere along the belt, indicates that the general structural relations 
are everywhere the same, though the veins have proved profitable in only 
a limited number of localities. 

General description of veins and country rocl'. —The veins belonging 
to the Tellurium system are situated in a series of fine-grained quartz- 
mica schists, usually garnetiferous, interbedded with fine-grained, even- 
granular quartzites, some of which contain much hematite and magnetite. 
All the gold-bearing veins observed occur either in quartzite beds, which 


156 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

are very narrow, or in the schists close to them. This series of sedi- 
mentaries is bounded on the northeast by a fine-grained granite, which 
in places, especially near its borders, contains areas of hornblende schist. 
Exposures are very rare except where openings have been made in pros¬ 
pecting for veins, so it is not possible to trace the exact boundaries of the 
granite area, but its field relations, the lack of schistosity in most places, 
and the extensive metamorphism exhibited by the schists in the vicinity, 
indicate that it is later in origin than the sedimentaries. The granite is 
exposed within less than half a mile of the Tellurium veins and probably 
comes much closer. Specimens found on one of the old dumps at the 
Tellurium indicate that there are probably apophyses from the granite, 
if not the main mass itself, within a few yards of the veins, and this 
hypothesis is supported by the extreme metamorphism of the rocks at the 
few places where they are exposed on the northeast side of the veins. 

The veins which have received the greatest amount of attention on the 
Tellurium property are known as the “Big Sandstone,” and “Middle,” and 
the “Little” veins. In addition to these the “Hodges” vein on the Scotia 
property and several other veins belonging to the system have been pros¬ 
pected to a limited extent. 

The so-called “Big Sandstone” vein consists of a bed of quartzite 2 to 
6 feet thick, cut in places by irregular gold-bearing veinlets, composed 
essentially of quartz with more or less feldspar and a little pyrite. (See 
fig. 12.) The veinlets range up to about 1 foot in width, and in their 
vicinity the quartzite is often impregnated with a very small amount of 
pyrite, chiefly along bedding planes, and carries a little gold. This bed of 
quartzite is remarkably uniform wherever it has been observed, and 
apparently extends continuously for a distance of 3 miles and possibly 
farther, but it is probably gold-bearing only in places and where it has 
been mineralized by the vein-forming solutions. It has an average strike 
of N. 64° E. and dips at an angle of about 45° toward the southeast. 

The outcrop of the “Middle” vein is parallel to the “Big Sandstone” 
and located about 30 feet southeast, dipping in the same direction at an 
angle of 43°. Where exposed it consists of a series of lenses varying from 
3 feet down to a knife edge in thickness, and is composed of quartz with 
variable amounts of feldspar, pyrite, largely oxidized to limonite, and a 
little gold. The lenses are enclosed by a thinly foliated, garnetiferous 
schist the folia of which conform to the flexures of the vein. (See fig. 
13.) 

The “Little” vein, which is not at present exposed, is said to parallel 
the “Middle” vein at a distance of 20 feet to the southeast. Descriptions 


THE GOLD MINES OF THE DISTRICT. 


157 


indicate that it is similar in character to the “Middle” vein but narrower, 
averaging less than a foot in width, and richer in gold. The deepest 
workings on the “Little” vein are said to have attained about 65 feet from 
the surface, but it usually pinched out before that depth was reached. 

A vein known as the “West” vein is exposed by a shaft 40 yards north¬ 
west of the “Big Sandstone” vein at the Tellurium. Where exposed it 
has a strike of N. 27° E., a dip of 80° to the east, and is about a foot 
wide. Quartz found on the dump yielded colors of free gold on panning. 
The nonconformity of this vein in strike and dip with the other veins of 
the Tellurium system, suggests that it may belong to the Gold Hill system 
described on pages 176-179, but the shaft was partly caved and the vein 
and wall rock could not be examined closely. 

The so-called “Hodges” vein, developed to some extent on the Scotia 
property, is a lenticular bed of ferruginous quartzite, which narrows from 
a width of over 6 feet to a fraction of an inch within a distance of only 
40 feet. The quartzite is cut by a few small stringers of gold-bearing 
quartz, which have mineralized the enclosing rock to a limited degree. 
While this quartzite pinches out and is not continuous in its course, as is 
true of the “Big Sandstone” bed, pieces of float similar in every way are 
plentiful at several points in approximate alignment with one another in a 
northeast-southwest direction. 

At a number of localities on the Scotia, Tellurium, and other properties 
along the course of the Tellurium vein system, there are bold outcrops of 
large veins, consisting of massive white quartz carrying a small amount 
of kaolinized feldspar. Some of these veins are 10 to 20 feet wide and 
can be traced for several hundred feet along the strike. They are reported 
to carry traces of gold but none of them have been worked. 

The wonderful uniformity and persistence of the bed of quartzite, 
known as the “Big Sandstone” vein, and hitherto regarded as a true vein, 
has given rise to a mistaken idea concerning the continuity of the veins in 
this district. The “Little” vein and the “Middle” vein and even the gold- 
bearing stringers in the “Big Sandstone” vein itself, are not continuous 
for great distances, though it is probable that sections across the vein 
system, at two or more points, would intersect approximately the same 
number of veins; for while the veins frequently pinch out, they may be re¬ 
placed by others a little to one side or farther along the line of strike. 

Detailed descriptions of veins and wall rock .—The sketch given in fig. 
12 shows the appearance and structural relations of the “Big Sandstone” 
vein in the northeast drive from the bottom of the new incline shaft at 


158 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


the Tellurium mine, which is about 65 feet from the surface; and this 
occurrence is typical of the vein wherever it could be observed. Here the 
quartzite bed is 6 feet thick, and distinctly laminated parallel to the 
bedding, the laminae being disturbed in places where the quartz veinlets 
cut across them. At the top of the bed the quartzite grades into a fine¬ 
grained quartz-sericite schist, and finally into the garnetiferous schist 
which forms the foot-wall of the “Middle” vein; but at the bottom the 
contact with the underlying rock is sharp and well defined. Below the 
quartzite there is a bed 4 to 5 inches thick, consisting for the most part 
of biotite, often altered to chlorite, large garnets, and a little feldspar. 
The rock underlying this bed is exposed for a short distance only. It is 
highly laminated and finer grained, but in mineral composition resembles 
the rock above except for the presence of more quartz. Detailed petro¬ 
graphic descriptions of all of these rocks are given below. 



SCALE 

0 1 2 3 4 Feet 

i-1_i_i_p 

Fig. 12.—Sketch of quartzite bed cut by gold-bearing veins, Tellurium mine. A, 
hanging wall schist; B, quartz-feldspar veins; C, quartzite; D, garnetiferous 
foot-wall layer; E, foot-wall schist. 









THE GOLD MIXES OF THE DISTKICT. 


159 


The individual veinlets in the quartzite range up to 14 inches or more 
in width, and commonly follow bedding planes though they frequently 
cut directly across. Where the bedding planes are cut by veinlets, little 
spurs from the quartz sometimes extend out along them for a short dis¬ 
tance. Lenses of vein quartz occasionally take the place of veinlets at the 
top of the quartzite, but rarely occur within the bed itself, and where seen 
were always small. The veinlets are composed essentially of white to 
translucent, coarsely crystalline quartz, and kaolinized feldspar is usually 
present, in places becoming an important gangue mineral. Pyrite is 
commonly a constituent in small quantity but rarely exceeds one per cent.; 
native gold occurs in small grains and scales that may usually be detected 
on panning the crushed ore; and sphalerite, tetradymite, and tellurium (?) 
have been identified as rare accessory minerals. In the oxidized zone near 
the surface, joint planes and fractures in the quartz are frequently stained 
with black oxide of manganese. 

The feldspar is distributed throughout the quartz veins in small angular 
shapes, but is more plentiful near the border portions where it sometimes 
forms small lenticular bands or streaks parallel to the walls, and may 
constitute as much as 10 per cent, of the mass. Rarely it occurs in 
lenticular masses 3 inches or more in maximum diameter. In most places 
where the vein is exposed the feldspars are completely altered to kaolin, 
and it is difficult to obtain specimens sufficiently fresh to admit of their 
determination. 

The freshest feldspars were obtained from a piece of vein quartz found 
on a shaft dump at the Scotia mine, and which evidently came from the 
foot-wall side of the quartzite bed, for some of the underlying rock was 
firmly attached. In the hand specimen (143-A) the feldspars occur in 
somewhat angular individuals ranging up to 0.75 cm. in diameter, and 
are white to light yellow in color and show good cleavage. While sparingly 
scattered throughout the quartz they are more plentiful near the contact 
with the country rock, forming perhaps 10 per cent, of the mass. A little 
chlorite, occurring chiefly near the contact, white mica and an infinitesimal 
amount of pyrite make up the chief minor constituents. A few thin plates 
of ilmenite occur in the quartz near the wall rock. Under the microscope 
the feldspars show extreme alteration to kaolin and sericite, but multiple 
twinning' can be detected on some of them, and this with the index of 
refraction identifies them as oligoclase-andesine.® There is probably some 

oTlie indices of refraction as determined by Dr. E. S. Larsen, Jr., using the 
immersion method, were Q( = 1.542 ± 0.003 and X— 1.551 ± 0.003. 



160 


GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIN. 


ortlioclase present but it could not be positively identified. The quartz in 
the slide shows some optical distortion and contains numerous gas- and 
liquid-filled cavities. 

Pyrite nowhere seems to be an abundant constituent of the veins cutting 
the quartzite. It is usually present in small quantities, rarely amounting 
to more than 1 per cent., and wherever observed was fine-grained. 

Gold occurs chiefly in the native state and can frequently be detected 
by panning. In a piece of the vein quartz obtained within 6 feet of the 
surface, close to the incline shaft at the Tellurium mine, gold is present 
in small flakes about 0.25 mm. in diameter. At greater depth much of 
the gold is probably contained in pyrite. 

A small amount of black sphalerite was identified in vein quartz from 
one of the stringers in the quartzite, but this mineral seems to be very 
rare in the veins of the tellurium system. 

Tetradymite has been identified in ore at the Tellurium mine, being 
first analyzed by Coleman Fisher, Jr., a and later by Dr. F. A. Genth. b 
The analysis given by the latter is as follows: 

Analysis of tetradymite from the Tellurium mine, Virginia, 

(Dr. F. A. Genth, analyst.) 

Per cent. 


Bismuth . 51.56 

Tellurium . 49.79 

Selenium . trace 

Sulphur . none 


Genth states that in the specimen examined by him tetradymite occurs 
“in broad folia, sometimes 1 inch in diameter, implanted in a decomposed 
micaceous slate. . . . Before the blowpipe it fuses readily giving out 

a faint but distinct odor of selenium, leaving on charcoal white incrusta¬ 
tions with a yellow center.” Elsewhere he states that the tetradymite 
from the Tellurium mine is frequently interlaminated with gold, and 
experiments made by him proved that gold was easily precipitated from 
dilute solutions by tetradymite. 0 His description of the gangue indicates 
that the specimen was probably obtained from the wall of the “Middle” 
or “Little” vein, rather than the veinlets in the quartzite bed, but these 
veins are all identical in their mineral composition and mode of formation. 

aAmer. Jour. Sci., vol. vii, 2d ser., p. 282. 

&Genth, F. A., Contributions to Mineralogy, Amer. Jour. Sci., 1855 vol. xix 
2d s*er., pp. 15-16. 

cGentli, F. A., Contributions to Mineralogy, Amer. Jour. Sci., 1859 vol xxviii 
2d ser., pp. 254-255. 







THE GOLD MINES OF THE DISTRICT. 


161 


Tellurium is mentioned by Credner as being present in the form of a 
coating together with gold, but the mineral seen by him was probably 
tetradymite.® 

In order to show the distribution of the gold and the relative degree 
of mineralization, average samples of the veinlets and of the quartzite were 
carefully taken in the face of the drive sketched in fig. 12. The elements, 
gold, silver, iron, and sulphur, were determined in each of these samples 
and are tabulated below. The percentage of pyrite given in the table was 
computed from the amount of sulphur found, based on the assumption 
that all of the sulphur present is in the form of pyrite, which is essen¬ 
tially correct. The excess iron is present chiefly in the form of limonite, 
with a little chlorite, and possibly some ilmenite. 


Partial analyses of ore from the Tellurium mine, Virginia. 
(E. E. Burlingame & Co., analysts.) 


Vein quartz. 

Quartzite. 

Gold (ounces) . 

0.12 

0.02 

Silver (ounces) . 

trace 

Iron (per cent.) . 

1 00 

3 60 

Sulphur (per cent.) . 

0 16 

0.41 

Pvrite (per cent.) . 

0.30 

0.77 



The quartzite which forms the greater portion of the “Big Sandstone” 
vein is fine-grained, even-granular, and light gray to almost white when 
fresh, turning to light brownish-gray or pink on weathering. The rock 
has distinct schistosity parallel to the bedding, and when examined on 
fractures that cut across the schistosity it appears to consist entirely of 
quartz, while on surfaces paralleling the schistosity fine scales of sericite 
can always be distinguished and are usually abundant, giving the quartzite 
a high luster. A little fine-grained pyrite may be recognized in places, 
but is never an important constituent. In a single instance, crystals of 
muscovite over 2 cm. in diameter were found in quartzite adjacent to 
one of the veinlets. 

In thin sections (Specs. 135, 147, and 189) under the microscope, the 
quartzite is composed essentially of interlocking quartz grains, less than 
1 mm. in maximum diameter and averaging about 0.25 mm., which are 
partially oriented with their greater diameters roughly parallel to the 
schistosity. The quartz grains are so extensively recrystallized that they 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 9. 
















162 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

furnish little evidence of their former size and shape. They usually show 
some optical distortion but little if any granulation, and contain occa¬ 
sional small fluid inclusions. Sericite is always present in small scattered 
flakes mostly parallel to the schistosity. The feldspars (orthoclase and 
acid plagioclase) are common in specimens of quartzite obtained near the 
veinlets, and seem to be rare or absent elsewhere in the quartzite. Where 
abundant the feldspars occur filling interstitial spaces between quartz 
grains, and in long, irregular, more or less broken lines parallel to the 
schistosity, indicating that they were formed later than the quartz, and 
suggesting that the feldspars may have been introduced into the rock by 
the vein-forming solutions. The feldspars are partly kaolinized and show 
some alteration to sericite. The alteration of the feldspars together with 
their low index of refraction render easy their differentiation from quartz 
even where twinning is absent. The minerals chlorite, zircon, titanite, 
rutile, and ilmenite, partly altered to leucoxene, are present in small but 
varying quantities as unimportant accessory constituents. 

The contacts between the stringers of vein quartz and the quartzite 
are well marked and easily recognized in the hand specimen because of 
difference in color and granularity, but under the microscope (Spec. 190) 
the contact is less sharply defined and is more of a gradation. The 
quartzite is completely recrystallized, so that the individual quartz grains 
interlock with those of the vein quartz, and the only difference between 
them is one of relative size. In the former the grains are seldom over 
1 mm. in diameter, while in the latter the quartz individuals average 
from 2 to 3 mm. The quartz grains in both vein and quartzite show 
irregular, interpenetrating boundaries, strain shadows, and slight 
peripheral granulation. The vein quartz is practically free from impurities 
other than minute gaseous and liquid inclusions. The quartzite contains 
much feldspar, chiefly orthoclase with some acid plagioclase, which shows 
slight kaolinization and partial alteration to sericite. Sericite in small 
flakes is distributed throughout the quartzite, pyrite is present, usually 
in small cubes, and the minerals chlorite and zircon occur as minor 
constituents. 

A specimen (188) found on an old dump at the Tellurium mine, con¬ 
tains a layer of rock 3.5 to I inches thick, which consists of fine-grained, 
impure quartzite, or schist interleaved with numerous narrow veinlets and 
lenticular eyes of quartz 1 mm. to 1 cm. in width. This layer was inter- 
bedded with the normal quartzite. Microscopic examination shows that 
the veinlets and lenses are composed chiefly of coarsely crystalline quartz. 


THE GOLD MIXES OF THE DISTRICT. 


163 


with minor amounts of feldspar—albite or albite-oligoelase and perhaps 
some orthoclase. The quartzite is very fine-grained and consists of quartz, 
feldspar, sericite, biotite, chlorite, pyrite, and a little titanite. The 
feldspars in the .veinlets frequently have good crystal outline and range 
up to 1 mm. or more in diameter. They usually occur near the border 
portions of the veinlets projecting into the fine-grained quartzite, and in 
places appear to be completely separated from the veinlets. These 
feldspars, while well formed, show rough outlines under the microscope, 
because along their boundaries the feldspars fill up the inequalities caused 
by irregularities in the adjoining quartz grains. Some of the feldspars 
show albite twinning but many are unstriated. 

By decrease of quartz and increase of mica the quartzite passes into 
the overlying schists. In the hand specimen (141) the rock from the 
hanging wall of the “Big Sandstone” vein, where it was cut by a vertical 
shaft at the Scotia mine, is a light brown, fine-grained, schistose quartzite; 
and in thin section under the microscope it is even-granular, being com¬ 
posed of roughly rounded quartz grains, showing little or no optical dis¬ 
tortion, and decreasing amounts of biotite, sericite, and chlorite. There is 
probably a little feldspar present, but it could not be positively identified. 
Some of the biotite shows partial alteration to chlorite. The minor acces¬ 
sory minerals are a little pyrite, chiefly along bedding planes, small grains 
of ilmenite, largely altered to leucoxene, and occasional inclusions of zircon 
and rutile. 

Another specimen (142) from the same locality is a fine-grained, light 
gray schist composed chiefly of quartz and sericite with scattered flakes 
of biotite and chlorite, and occasional garnets 1 to 3 mm. in diameter. 
Other minerals present are pyrite, zircon, titanite, and leucoxene. 

Between the quartzite and the middle vein the rock is mostly a fine¬ 
grained, light bluish-gray schist composed essentially of quartz, sericite, 
and biotite. In places it contains impure garnets 1 to 2 mm. in diameter, 
and sometimes there is much fine-grained pyrite present. 

The thin strip of rock underlying the quartzite (see fig. 12) in many 
wavs resembles the garnetiferous bed that occurs on the east side of the 
quartzite near New Canton (see pp. 107-108), and elsewhere, except that no 
sillimanite or cyanite could be identified in the rock at the Tellurium 
mine. In color the rock varies from dark gray where freshest to dark brown 
or greenish-brown. It consists chiefly of numerous reddish-brown garnets 
ranging up to 5 mm. in diameter, imbedded in a schistose ground-mass of 
biotite usually altered to chlorite. In thin sections (Specs. 186-A and -B) 


164 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

under the microscope much feldspar—both acid plagioclase and orthoclase 
—can be distinguished, and the minerals, quartz, ilmenite, mostly altered 
to leucoxene, pyrite, and sericite, are also present. The garnets occur in 
well-formed dodecahedrons containing inclusions of ilmenite and leucoxene. 
The biotite is light brown in color and in some specimens is largely altered 
to chlorite. The feldspars are extensively kaolinized, contain inclusions 
of biotite and chlorite, and in places show albite twinning. 

This strip of foot-wall rock was encountered at the Bowles and Scotia 
mines as well as at the Tellurium. Pieces of vein quartz were found on 
the dump at the Bowles mine with some of the foot-wall adhering, which 
contained garnets over 1 cm. in diameter, partly imbedded in the vein 
quartz and partly in the wall rock. 

At the Scotia mine dark green hornblende is found in places where the 
vein quartz, containing feldspar, occurs in contact with the rock under¬ 
lying the quartzite. Occasionally small veinlets extend from the quartz 
vein out into the country rock and these carry much feldspar, white to 
yellow in color. The hornblende is present in the wall rock close to the vein, 
sometimes being the chief constituent, and does not seem to extend farther 
than 3 or 4 inches from the contact with the vein. This hornblendie rock 
grades into the normal biotite-chlorite-garnet schist described above. 
Examined microscopically (Spec. 143-B) the hornblende is light green to 
colorless, and shows alteration to chlorite and epidote. Quartz occurs in 
irregular grains showing optical distortion. Much titanite is present in 
clear, light pink to colorless grains, well-formed crystals of rutile occur 
as inclusions in the quartz, and ilmenite is also a minor constituent. Both 
rutile and ilmenite show partial alteration to leucoxene. 

A specimen (194) of the rock underlying the narrow strip described 
above was obtained in the face of the northeast drive from the Tellurium 
incline shaft (E in fig. 12). It is a light brown schist similar in mineral 
composition to the overlying rock, except that it is finer grained and more 
siliceous. The minerals present are quartz, biotite and chlorite, garnet, 
feldspar, sericite, pyrite, leucoxene derived from ilmenite, and titanite, 
the order given being that of relative abundance. The quartz grains are 
small and show little optical distortion. Biotite is present in brown flakes 
containing occasional inclusions of quartz, and is extensively altered to 
chlorite. The garnets are light pink in color and show slight alteration to 
chlorite along fractures. They contain numerous inclusions of quartz, 
pyrite, and ilmenite partly altered to leucoxene. The feldspars—orthoclase 
and acid plagioclase—are extensively kaolinized. 



THE GOLD MINES OF THE DISTRICT 


1G5 


I lie Middle 'ein is conformable in strike and dip with the enclosing 
schists, and therefore parallel to the quartzite bed. It is extremely variable 
in width, consisting of a series of small lenses which range up to 3 feet or 
moie in thickness; and these lenses are all strung out along the same line, 
being usually connected by a narrow stringer. (See fig. 13.) In this 
respect the “Middle'’ vein is markedly different from the veinlets in the 



SCALE 

03 6 9 12 Inches 


Fig. 13.—Diagrammatic sketch showing symmetrical lenses of the middle vein at 
the Tellurium Mine. Q, quartz; F, feldspar; A, hanging wall schist; C, foot- 
wall schist; B, bed of light-colored schist. 

quartzite, for the latter are seldom lenticular in shape, frequently cut 
across the bedding of the enclosing rock, and are variable in their strike 
and dip. 

The lenses forming the “Middle” vein are separated in places by a 
distance of several feet, and the veinlets connecting them may pinch to 
almost nothing so that only a faint line remains, but it can usually be dis¬ 
tinguished without difficulty. In the partly decomposed schists near the 
























































































































166 


GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIN. 


surface this line is marked by the dark stain of oxides of iron, probably 
from the alteration of pyrite; and when the soft material is broken away 
a little coarse grit, due to the presence of quartz, can be detected on the 
line. Feldspar is an important constituent of this vein, but in the open¬ 
ings that are now accessible it is completely altered to kaolin. The kaolin 



SCALE 

01234 Feet 

K~ _ =ri -1 . -- I 


Fig. 14.—Vertical section of middle vein at the Tellurium Mine, showing large lens 
composed of smaller lenses. 

occurs in small angular shapes distributed throughout the quartz, but is 
mostly found along the border portion of the lenses, and especially at 
points where they narrow and pinch out. (See fig. 13.) Some of the 
smaller lenses 2 or 3 inches in length are composed entirely of kaolin. In 
places the larger lenses are made up of a number of smaller ones as shown 















THE GOLD MINES OF THE DISTRICT 


167 


in fig. 14, and where this occurs there is occasionally a little schist in¬ 
cluded between the component lenses. At one point the vein is cut by a 
vertical fault which displaces the vein about 2 feet. (See fig. 15.) 



Fig. 15.—Vertical section showing symmetrical lenses of the middle vein of the 
Tellurium Mine, and a small fault. Q, quartz-feldspar lenses; A, hanging wall 
schist; C, foot-wall schist; B, bed of light-colored schist. 

The formation of the peculiar lenses which constitute the “Middle” 
vein is discussed in detail in the chapter on genesis, pages 224-230, and-- 
therefore nothing further concerning them will be said here. 

The “Middle” vein is similar in mineral composition to the veinlets 
that cut the quartzite bed and constitute the chief gold-bearing portion 
of the “Big Sandstone” vein, but it probably contains a larger percentage 
of feldspar. According to report, the “Middle” vein is much richer in 
gold than the “Big Sandstone,” and this is unquestionably true if the 
whole bed of quartzite is included with the veinlets, but it is questionable 
whether the average value of the gold-bearing veinlets that occur in the 
quartzite is greatly below that of the “Middle” vein. An average sample, 

































168 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

taken across a lens in the vein 2 y 2 feet wide, yielded $2.07 gold per ton, 
but it should be understood that this does not represent the average value 
of the vein. The best ore seems to occur in pockets or shoots, and much 
of the ore that has been stoped out unquestionably carried high values in 
gold. An ore pile on the surface showed much gold when tested by pan¬ 
ning, and specks of visible gold are not infrequent in fragments of the ore. 
The wall rocks apparently are not mineralized to any appreciable extent. 

The “Middle” vein is enclosed in a series of fine-grained, knotted 
schists, containing pseudophenocrysts of garnet. The folia of the schists 
in the immediate vicinity of the vein are wrapped around the lenses, con¬ 
forming to every curvature of the ore-body, but in passing away from the 
vein the flexures gradually disappear, and at a short distance the folia 
are straight and undisturbed. (See fig. 13.) 

The vein appears to follow a bed of light-colored schist 2 to 2)4 feet 
thick interbedded with darker schists. Where exposed these rocks are so 
badly altered that it is not possible to obtain material sufficiently fresh 
for microscopic examination. The light-colored schist is composed essen¬ 
tially of quartz and sericite, with small, scattered brown spots due to the 
alteration of garnet. Along fractures and joint planes it is stained with 
iron, but elsewhere it is almost white in color. The overlying schist is light 
bluish-gray, and contains decomposed garnets 3 or 4 mm. in diameter, 
embedded in a fine-grained ground-mass. The folia of the schist are 
wrinkled or folded to form lenticular eyes around the garnets. The under¬ 
lying schist is similar to the one last described excepting that the garnets 
are less numerous and smaller in size. 

Pieces of unaltered garnetiferous schist, similar to the decomposed 
schist described above, were found on the dump of the 136-foot vertical 
shaft sunk in the hanging w T all of the Tellurium veins. In the hand speci¬ 
men (178) it is a thinly foliated, fine-grained, bluish-gray rock with high 
luster on surfaces parallel to the schistosity, and is spotted with numerous 
garnets in well-formed dodecahedrons 1 to 2 mm. in diameter. With the 
aid of a pocket lens, quartz, sericite, and biotite may be identified as the 
chief minerals of the ground-mass. Under the microscope the garnets are 
seen to be full of small inclusions consisting of grains of quartz, ilmenite 
partly altered to leucoxene, and a black opaque mineral in dust-like 
particles, possibly ilmenite. The ground-mass is composed of small ir¬ 
regular grains of quartz, with flakes of sericite, biotite, and chlorite, all 
of which are crowded with the black dust-like inclusions. Leucoxene is 
plentiful in grains which frequently contain nuclei of unaltered ilmenite. 


THE GOLD HINES OF THE DISTRICT. 


169 


Occasionally the garnets are partly or wholly surrounded by a zone from 
which most of the minerals other than quartz have disappeared, probably 
entering into the composition of the garnet; and the quartz has recrystal¬ 
lized into small, elongated grains, with their longer diameters oriented in 
approximate alignment with radii extending from the garnet. (See PI. V, 
fig. 2.) 

Pieces of rock, evidently igneous in origin, were found on the dump 
of an old shaft, which was sunk in developing the “Big Sandstone” vein 
at the Tellurium mine, but is now completely caved. In the absence of 
chemical analyses or knowledge of the structural relations, it is impossible 
to definitely classify this rock, but it is not improbable that it is genetically 
related to the granite on the northwest. In the hand specimen (185) 
the rock is light gray in color, fine-grained, and very schistose. Roughly 
formed, reddish-brown garnets and small flakes of biotite can be distin¬ 
guished in a white ground-mass composed of quartz and feldspar. 
Examined in thin section, feldspar phenocrysts are seen, ranging up to 
2 mm. in length, which, with flakes of biotite about 0.5 mm. in length and 
irregular garnets, occur in a fine-grained ground-mass composed of quartz, 
feldspar, biotite, a little sericite, and inclusions of leucoxene, zircon, 
titanite, and rutile needles. The feldspars are acid plagioclase (albite- 
oligoclase ( ?) ) and orthoclase, the larger individuals have very irregular 
outlines, and they contain numerous fluid-filled cavities and small inclu¬ 
sions of zircon and the titanium minerals. 

A different appearing igneous rock found on the same dump is much 
more schistose than the one previously described, and may represent an 
interbedded acid extrusive, or a dike rock older in age than the granite 
and its differentiates. It contains numerous garnets 1 to 2 mm. in 
diameter and flakes of biotite, embedded in a light brown, schistose ground- 
mass, composed essentially of feldspars, more or less kaolinized. Examined 
under the microscope the garnets are very ragged in outline and contain 
numerous inclusions of quartz. Feldspars, chiefly soda plagioclase, are 
dominant in the thin section, though a little orthoclase is present. Some 
of the larger feldspars are bent and broken, the fractures being filled by 
minerals of later crystallization. The minor constituents are quartz, 
pyrite, and leucoxene. 

The hypothesis that these rocks are genetically connected with the 
granite is strengthened by the presence on one of the dumps of horn- 
blendic schists, such as are found in the immediate vicinity of granite 
throughout the area. A hand specimen (179) of hornblende schist found 


170 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

on the dump of the 136-foot shaft at the Tellurium mine, consists of 
coarse-bladed crystals of dark green hornblende ranging up to 1.5 or 2 cm. 
in length, and white, fine-grained quartz and feldspar. Small grains of 
pyrrhotite, pyrite, and magnetite are plentifully distributed throughout 
the rock. Under the microscope the hornblende is ragged in outline, and 
micropoikilitic in texture from numerous inclusions of quartz, magnetite, 
and pyrite. The cleavage is well developed and they are usually dark green 
in color, though some are nearly colorless. The quartz occurs in small 
rounded grains and is difficult to distinguish from the unstriated feldspar. 
The latter is acid plagioclase; probably no orthoclase is present in the 
rock. Magnetite is plentiful in small idiomorphic grains. Calcite and 
fibrous serpentine occur as vein-filling in a microscopic fracture. 

Another variety found on the same dump is much finer grained. It is 
a greenish-gray schistose rock (Spec. 180) in which quartz, hornblende, 
magnetite, pyrite, and a little sericite can be distinguished with the aid of 
a pocket lens. In thin section the hornblende occurs, partly in dark green 
to colorless crystals with well-developed cleavage and strong absorption 
in the darker varieties, and partly in nearly colorless needles often 
clustered together in radiating groups. Quartz and an unstriated feldspar, 
probably acid plagioclase, are present in rounded grains showing little 
optical distortion. Much magnetite, in idiomorphic crystals ranging up 
to 1 mm. in diameter, is plentifully distributed throughout the rock. 

The lenticular bed of ferruginous quartzite, known as the “Hodges” 
vein, which has been developed to some extent at the Scotia mine, is 
situated about 600 yards southeast of the course of the “Big Sandstone” 
vein. The few exposures in the vicinity indicate that the quartzite is inter- 
bedded with quartz-sericite schists. A small prospect pit, located about 
300 yards northeast of the openings on the “Hodges” vein and approxi¬ 
mately in line of strike, exposes a thinly foliated schist, which in the hand 
specimen (211) appears to be composed entirely of sericite and quartz. 
It is white in color when not stained with limonite, and contains occa¬ 
sional eyes of light blue opalescent quartz about 0.5 cm. in length. The 
strike of the schistosity is 1ST. 60° E. and the dip 30° toward the southeast. 

The shape of the quartzite bed, where it is exposed by short drives from 
the bottom of the incline shaft, is shown in fig. 16. The maximum width 
is over 6 feet, and from this the bed tapers down to a fraction of an inch at 
either end. The average dip is southeast 35° and the strike about X. 40° E. 
Although the quartzite apparently pinches out at either end of the lens, 
much float rock identical in appearance and composition occurs on the 


THE GOLD MINES OF THE DISTRICT. 


171 


surface about three-quarters of a mile northeast, and at several other points 
in the same general alignment. 

Megascopically the quartzite is fine-grained, even-granular, and some¬ 
what variegated in color because of local concentration of the various oxides 
of iron. In places the rock is white to light gray in color, consisting chiefly 
of quartz, with only a small amount of iron in the form of specular hematite 
and octahedral crystals of magnetite. Elsewhere the rock is dark brown 



Fig. 10.—Horizontal plan showing lenticular shape 
of ferruginous quartzite bed exposed in under¬ 
ground openings at the Scotia mine. 


to black in color and contains a larger percentage of the iron minerals, 
which are usually extensively altered to limonite. The two colors are 
irregularly intermixed, blotches of white being enclosed in areas that are 
dark brown in color and vice versa. Xear the center of many of the dark 
areas, much fine-grained magnetite is found, and along the contact between 
the light and dark areas there is often a narrow, red-colored band, probably 
due to iron stain on the quartz grains. 





172 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

In thin section (Spec. 153) under the microscope the rock is essen¬ 
tially the same as the non-gold-bearing ferruginous, quartzites which occur 
at a large number of localities in the area, described in detail on pages 19-22. 
The quartz grains are roughly rounded, nearly uniform in size, averaging 
about 0.25 mm. in diameter, and show no optical distortion. This close 
interlocking texture is due to recrystallization, which probably resulted in 
some enlargement of the individual grains. Small idiomorphic inclusions 
of martite (magnetite altered to hematite) are present in the quartz; and 
the larger masses of iron ore, occurring between the quartz grains, show 
considerable alteration to limonite, which in many places stains the 
boundaries of the other minerals. Zircon and a few small rutile needles 
are unimportant minor constituents. 

The quartzite is cut by occasional irregular stringers of quartz, which 
range up to 10 inches or more in width, and very rarely contain vug-like 
cavities lined with quartz crystals. The stringers occur mostly on the 
foot-wall side of the quartzite. They carry a little pyrite largely altered 
to limonite, and probably a small amount of feldspar, though the latter 
mineral was not positively identified. The presence of gold is easily 
detected by panning, and sometimes small specks of free gold can be 
identified in hand specimens, usually in association with limonite derived 
from pyrite. 

Tests made by panning indicate that the quartzite away from the gold- 
bearing veinlets carries little if any gold. Sometimes a small amount of 
pyrite may be found in the quartzite near the veinlets, but most of it occurs 
as a coating along fractures and is evidently secondary in origin. 

The Scotia Mine. 

Location .—The Scotia property is situated about half a mile north of 
Caledonia and 7 miles northeast of Columbia. It adjoins the Tellurium 
mine and is crossed by the southwestern extension of the same vein system. 

History and description .—This property was formerly known as the 
Perkins mine and under that name was prospected in the early days of gold 
mining in Virginia. According to Credner the ore used to pay the working 
expenses. After 1849 very little work was done until the Scotia Mining 
Co. began prospecting in 1910. An account of the development work is 
given below and a detailed description of the veins and country rock will be 
found on pages 157 to 172. 

A drain tunnel was driven 105 feet in a direction S. 11° E., cutting 
the “Big Sandstone'’ vein near the portal and also two small stringers 
that were called the “Middle” and “Little” veins. The country rock is 
much decomposed, but where fresh enough for identification consisted of 


THE GOLD MINES OF THE DISTRICT. 


173 


knotted garnetiferous schists similar to those at the Tellurium mine. A 
67-foot vertical shaft sunk in the hanging wall, cut the “Big Sandstone” 
vein near the bottom. It was partly filled with water when the property 
was examined by the writer, but much fresh rock was exposed on the dump 
and this is described, together with the veins of the Tellurium system, on 
pages 157 to 164. The “Big Sandstone” vein was exposed in a pit sunk on 
the outcrop 100 feet northwest of the vertical shaft. Here the quartzite 
bed had a strike of N. 50° E., a dip of 35° southeast, and varied from 
8 inches to 3 feet in width, averaging about 18 inches. It is cut by vein- 
lets of massive white quartz carrying considerable kaolinized feldspar. 
The same vein has been prospected on this property by several other sur¬ 
face cuts. 

An old incline shaft near the western boundary of the property was 
reopened by the Scotia Mining Co. It was sunk on a vein called the 
“Middle” vein, which has a maximum width of 2 feet about 12 feet from 
the surface and pinches to an inch near the bottom, 25 or 30 feet from the 
surface. The strike is approximately N. 60° E. and the dip 35° southeast. 
The enclosing rock, consisting of knotted, garnetiferous schist, is conform¬ 
able in strike and dip, and is cut by vertical joint planes, spaced 12 to 18 
inches apart, which have a strike of N. 44° W. It is improbable that this 
vein is continuous with either of the stringers in the drain tunnel or with 
the “Middle” vein at the Tellurium. Small stringers like these are not 
as a rule continuous for great distances but pinch out and are replaced 
by others a little farther along the line of strike. 

Near the southwestern corner of the Scotia property there is a bed of 
ferruginous quartzite cut by small gold-bearing stringers, which is known 
as the Hodges vein. It has been developed by several surface cuts and an 
incline shaft on the vein, 43 feet deep, from which short drives were run 
in northeast and southwest directions. A detailed description of the ore 
and country rock is given on pages 170-172. 

Gold Prospects Southwest of the Scotia Mine. 

Passing southwest along the strike of the Tellurium vein system, old 
prospect holes are found at short intervals as far as Big Byrd Creek, but, 
while gold has been found at a number of these places, very little develop¬ 
ment work has been done. 

On the Jennings tract adjoining the Scotia there are several old shafts 
and surface pits located along the strike of the Tellurium veins, but these 
are now caved and do not seem to have reached a depth of more than 40 


174 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

feet. Knotted garnetiferous schist, having a strike of K. 60° E. and 
dip of 30° southeast, is exposed in one of the openings, and quartzite 
similar to that at the Tellurium mine is present on one of the shaft dumps. 

By means of surface cuts, the quartzite bed has been traced across the 
Mosby, Fountain, and Cocke properties, and placer gravels have been 
worked along the branches that run through them and enter Big Byrd 
Creek. It is said that the “Big Sandstone” vein was prospected on the 
Fountain property in 1837 by Geo. Fisher, and another vein, known as the 
Marks vein, was also opened and worked to some extent. The ore was 
crushed in a small 3-stamp mill on Horsepen Creek and yielded $75 
per day.® 

Some mining has also been done on the old Bartlett place in this 
vicinity. Gold was discovered in the Bartlett Branch, which enters Big 
Byrd Creek from the east a short distance above Bowles’ bridge, and the 
placer gravels are said to have been worked by the Fishers. Later the 
Bartlett vein was discovered and prospected and a little mining done. The 
ore from this vein was carried to Bowles’ Mill on Big Byrd Creek and 
crushed in a small wooden stamp mill operated by the same power that 
ran the grist mill. 

Recently some prospecting has been done on a part of the old Payne 
farm, now known as Cassell’s mine. The place is situated on the county 
road about 2 miles northwest of Caledonia and 3 miles southwest of Kent’s 
Store. A small amount of ore has been mined and milled but all the work 
has been of a superficial nature. Several shafts and cross-cuts, all above 
water level, have been sunk in decomposed rock, and the only veins exposed 
when the openings were examined by the writer, consisted of a few quartz 
stringers less than an inch in width. Part of the workings are in a de¬ 
composed dike-like rock about 20 feet wide which appears to be pegmatite. 
It is not well exposed but has a probable strike of N. 6° E. 

Close to the other openings a pit has been sunk on a highly ferruginous 
quartzite bed 8 feet or more in thickness. The quartzite is dark brown with 
occasional light-colored spots, and is cut by closely spaced joints. It is com¬ 
posed of fine-grained quartz, hematite, and a little magnetite, and the 
light spots seem to be due to recrystallization of silica. In places along 
cracks or cleavage planes a crust of magnetite has been formed consisting 
of crystals 2 to 3 mm. in diameter. The quartzite is cut by quartz vein- 
lets 1 to 2 inches in width which frequently contain plates of micaceous 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, pp. 42-43. 



THE GOLD MINES OF THE DISTRICT. 


175 


hematite. Examined under the microscope (Spec. 209) it seems to have 
undergone greater recrystallization than the other ferruginous quartzites 
of the area. The quartz grains lack uniformity in size and are irregular 
in outline; they usually show optical distortion and contain comparatively 
few inclusions of the iron ores, while the larger masses of hematite contain 
small inclusions of quartz. The iron ores are partly altered to limonite, 
and the latter in places stains the contacts between the quartz grains. 

The Bowles Mine. 

Location .—The Bowles property is situated IT/b miles southeast of 
Tabscott and about 8 miles northeast of Columbia. It lies east and north¬ 
east of the Tellurium mine, and embraces a large area of land in both 
Goochland and Fluvanna counties. 

History and general description .—The placer gravels along the two 
branches that run through the property were extensively worked for gold 
prior to the Civil War. After the veins of the Tellurium system had been 
developed on the property of that name, they were traced across on to the 
Bowles tract and prospected at several points. Prospecting has been re¬ 
newed at several different periods and considerable development w r ork 
carried out. A shaft started on the outcrop of the “Big Sandstone” vein 
w r as sunk about 100 feet on the dip of the vein, and 50 feet from the collar 
a cross-cut was driven southeast to connect with a vertical shaft at a point 
about 40 feet below the surface. The vertical shaft was sunk to a depth of 
72 feet, and after striking the “Little” vein was continued for 45 feet 
along the dip of the vein. When visited by the writer in 1910 the shafts 
were partly filled with water and all the workings inaccessible. The data 
given above w f ere furnished by Mr. Ferris, who was in charge of the 
property at the time. The character of the veins and the structural rela¬ 
tions of the wall rock, which are the same as at the Tellurium mine, are 
described in detail on pages 157 to 172. 

The Gold Hill vein system crosses the northwestern end of the Bowles 
property, and several of the veins belonging to it were prospected at an 
early date. A number of shafts and other openings have been made, but 
practically all of them are now caved. The most extensive workings are 
located on the Gold Hill vein, and the Shaw or Back Field vein. Ores 
from the former vein were hauled to the Tellurium mill for treatment 
when mining w r as in progress about 25 years ago. A little work has been 
carried on recently by Mr. Ferris, who mined a few tons of high-grade 
ore from a small opening on the Back Field vein and crushed it in the 
Tellurium mill. The veins belonging to the Gold Hill system are described 
in detail below. 


GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIN. 


176 


The Gold Hill Vein System. 

Introduction .—The Gold Hill vein system is situated about 2 miles 
southeast of Kent’s Store and 2 miles west of Tabscott, and extends for a 
mile or more in a general northeast-southwest direction. It consists of a 
series of small veins, which show a greater variation in strike and dip 
than is found elsewhere in the district, but none of them seems to be very 
persistent. The veins have been developed to some extent at several places 
on the Bowles, Shaw, and McGloam properties, but all the work has been 
rather superficial in its nature. These veins differ from other veins of 
the district in several important characteristics besides their lack of uni¬ 
formity in strike and dip. They are located in an area of fine-grained 
granite, and are the only known gold-bearing veins within this district 
that occur in granite. The veins are characterized by the presence of 
coarsely crystalline pyrite, which frequently occurs in large cubical shapes 
1 cm. or more in diameter. 

Country rod .—There are few exposures of the country rock except 
where openings have been made in prospecting the gold veins. The 
dominant rock is a fine-grained granite, and this contains areas of horn¬ 
blende and chlorite schists, which are more noticeable near the border 
portions. Because of the extensive decomposition of the rocks in this 
section it is not possible to accurately map the boundaries of this granite 
area, but it has a width of more than one mile, and extends for an unknown 
distance in a northeasterly direction, probably connecting with the main 
granite batholith that lies to the east. 

The granite where freshest is a light gray, fine-grained rock, with 
scarcely any schistosity. The minerals visible to the naked eye are quartz 
and feldspar, with numerous small flakes of dark green chlorite, a little 
sericite, small cubes of pyrite, and occasional grains of magnetite. In 
thin sections it varies from granitic to granophyric in texture, intergrowths 
of quartz and the feldspars being common, and in places very abundant, 
while small phenocrysts of feldspar are present in some of the rock. The 
feldspars are acid plagioclase and orthoclase, with sometimes a little micro- 
cline. The white mica is apparently all secondary, and frequently shows 
intergrowths with quartz. The chlorite is probably derived from biotite. 
a mineral which is present in small quantities only. Calcite is plentiful 
in some slides and is probably derived chiefly from the feldspars. The 
minor constituents occurring in the rock are zircon, leucoxene, apatite, 
and rutile needles, while fluid inclusions are numerous in some of the 
quartz grains. (Specs. 82, 83, 158, 161, and 166.) 


THE GOLD MIXES OF THE DISTRICT. 


177 


The hornblende schist is exposed at several points in narrow hands 
interleaved with granite, and also in areas at least several hundred feet 
across. These schists are similar to the corresponding schists in the larger 
granite area, and are doubtless the same in origin. The rock is dark green 
in color and varies from medium coarse- to fine-grained. Hornblende, often 
largely replaced by chlorite, quartz, and feldspars, are the chief constituents; 
pyrite and magnetite can usually be recognized megascopically; and in 
some of the rock small grains of rutile and ilmenite can be identified. 
Under the microscope the larger hornblendes are ragged in outline and 
micropoikilitic from numerous inclusions of quartz and magnetite. The 
feldspars (acid plagioc-lase) are clear, unstriated, and difficult to distin¬ 
guish from quartz except by their lower index of refraction. Occasional 
grains of titanite, inclusions of zircon, and small rutile needles constitute 
the minor accessories. (Specs. 80, 81, 159, 160, 165, and 167.) 

Granite is the principal rock composing the dumps from shafts sunk 
on veins belonging to this system, and the hornblende schist is present in 
smaller amounts or entirely absent. 

The McGloam mine .—The McGloam mine is situated half a mile north 
of the Tellurium and joins the Bowles property which lies to the east. 
There are 2 shafts on the property 300 yards apart, one vertical and the 
other on a flat incline, but both are now filled with water. A vein, 1 to 2 
feet wide, is exposed in the mouth of the incline shaft. It has a strike of 
N. 70° E. and dips southeast at an angle of 30°. The fine-grained granite, 
a little hornblende schist, and considerable vein quartz are present on the 
dump. 

The vein quartz contains much coarsely crystalline pyrite, and in some 
pieces this has been partly or wholly removed, leaving cavities in the 
quartz which frequently show no staining from oxides of iron. A little 
free gold can sometimes be detected by panning. In places the vein quartz 
is interleaved with narrow bands of fine-grained granite which in the hand 
specimen resembles quartzite, for it contains practically no ferromagnesian 
minerals. A thin section (162) examined under the microscope, contains 
a veinlet of quartz 3 mm. wide enclosed by granite. The veinlet has 
sharply defined boundaries and is composed of quartz, containing numerous 
fluid inclusions, a very little feldspar, and some sericite. The enclosing 
rock is granitic to granophyric in texture, and consists of irregular rounded 
grains of quartz and feldspar, with a fine intergrowth of feldspar and 
quartz filling the interstitial spaces. The feldspar is chiefly acid plagio- 
clase, usually showing albite twinning, but orthoclase is also present and 


178 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


occasionally forms Carlsbad twins. A few flakes of sericite, small, 
scattered grains of magnetite, inclusions of zircon, and minute rutile 
needles make up the minor accessory minerals. A piece of granite found 
on the dump was cut by a stringer of quartz 1 inch in width, which con¬ 
tained small vugs lined with quartz crystals. 

Fine-grained granite and vein quartz were found on the dump of the 
vertical shaft, but no hornblende schist. The vein quartz (Spec. 162) 
contains coarsely crystalline pyrite, and angular inclusions and irregular 
streaks of the country rock. The inclusions, which are often large, give to 
the weathered rock the appearance of pegmatite. They are composed 
essentially of fine-grained feldspar and quartz which under the micro¬ 
scope are seen to be closely intergrown. The vein quartz shows little 
optical distortion and contains numerous fluid inclusions, usually arranged 
in long, broken lines which may pass without interruption from one 
individual to another. 

The Shaw mine .—The Shaw property is situated 14/2 miles northeast 
of the Tellurium mine, and on the east side of the northern portion of the 
Bowles tract. There are several shallow shafts located close to the small 
branch which passes through the property, but they are now partly caved 
and filled with water. They are said to have been sunk on the Shaw vein 
which has a strike of X. 80° E. Granite and hornblende schist were 
found on the dump, and the former rock outcrops at several places in the 
vicinity. 

The Bowles mine .—The Bowles property is described on page 175, 
and therefore only the veins belonging to the Gold Hill system will be 
mentioned here. 

Xear the northern end of this property there are several pits and small 
shafts, which are said to have been sunk on the “Shaw” vein, or “Back 
Field” vein as it is sometimes called. Only one of the openings was- 
accessible when the property was examined by the writer, and this was not 
over 30 feet in depth. The vein where it is exposed varies from 1 foot 
down to a fraction of an inch, but Mr. Ferris, who was in charge of the 
property, states that in places it attains a width of 4 feet. The strike is 
about X. 60° E. and the dip 30° southeast, so it is hardly probable that 
this vein is the extension of the one opened on the Shaw property. In 
places the vein carries considerable pyrite, partly altered to limonite, and 
at such points it is said to be rich in gold. A specimen examined In the 
writer contained grains of gold 2 mm. in diameter. Some of the vein 
quartz found on the dump contains cavities, evidently left by the oxida- 


THE GOLD MIXES OF THE DISTRICT. 


179 


lion and removal of pyrite, for some of them are partly filled with limonite; 
and attached to the walls of these cavities are numerous octahedra of 
magnetite 1 mm. and less in diameter. The wall rock where exposed con¬ 
sists of kaolin and quartz stained with a little iron, and is undoubtedly 
residual decay from the fine-grained granite found elsewhere in the 
wicinity. 

About 500 yards south, a vein 1 foot in width is exposed by a small pit. 
It has a strike of N. 22° E. and is nearly vertical. The quartz contains 
•coarse cubical crystals of pyrite similar to those found in the other gold- 
bearing veins in this granite area. Between this point and the McGloam 
vein numerous openings have been made, but they are not in perfect align¬ 
ment and the veins which were prospected seem to have different courses. 
The greatest amount of development work was done at a point where the 
Gold Hill vein, running northeast-southwest, is said to be intersected by 
the “Cross” vein. There are several shafts and pits now caved along the 
•course of the latter vein, which has a strike of 1ST. 30° W., and is said to 
dip southwest at an angle of about 35°. This work was done many years 
ago and little is now known concerning these veins. A piece of quartz 
containing small prisms of black tourmaline was picked up near the out- 
•crop of the “Cross” vein. 

The Page Mine. 

The Page mine is located in Fluvanna County on Long Island Creek a 
mile west of Wilmington. The veins on this property were first mined 
in 1856 and an 8-stamp mill was built to crush the ores.® According to 
Credner the ore was derived from 2 quartz veins, carrying fine-grained 
galena and gold, which were opened by several tunnels and shafts. 6 The 
mill was in ruins at the time of his visit in 1865. It is reported that 
prospecting was renewed about 1895, but no mining seems to have been 
done. 

When the property was visited by the writer in 1911 the only accessible 
opening was a tunnel about 20 feet long which ran under the hill on the 
west side of the creek. The country rock exposed in the tunnel is a partly 
decomposed slate but no vein could be seen. Most of the work was done 
•on the east side of the creek where there is an old caved tunnel, and on 
the hill above it several pits and open cuts. Xo rock was exposed on this 
side of the creek, but on the tunnel dump large pieces of vein quartz were 
foum and some of them contained inclusions of chloritic slate, and narrow, 
irregular veinlets of calcite. 

aNitze, H. B. C., and Wilkins, H. A. J., Gold Mining in North Carolina and 
Adjacent Appalachian Regions, Bull. 10, N. C. Geol. Survey, 1S97, p. 75. 

&Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
■Carolina, Amer. Jour. Mng., 1869. vol. vii, pp. 42-43. 



ISO GEOLOGY OF THE GOLD BELT IX THE JAMES LIVER BASIN. 

The gold-bearing gravels along Long Island Creek and some of its 
tributary branches have been worked, and gold nuggets worth $20 to $25 
were found on one of the properties a short distance up the creek from the 
Page mine.® Placer mining is said to have been carried on as late as 1865. 

About l 1 /? miles up stream from the Page mine there are several 
openings and a tunnel 100 to 200 feet in length which are said to have 
been made by Commodore Stockton. Credner states that a series of 
lenticular quartz concretions were exposed by an incline on top of the 
hill. The ore was a very hard, sandy quartz, carrying free gold in minute 
particles. Another quartz vein, nearly 60 feet wide, was exposed by pros¬ 
pecting pits but the ore was very poor. 6 

On several properties lying 1 y 2 to 2 miles north of Wilmington a little 
gold has been found in the placer gravels along the branches, and some 
quartz veins in that vicinity have been prospected by openings now caved, 
but all of the work seems to have been very superficial. 

The Snead Mine. 

Location .—The Snead mine is situated in Fluvanna County, 1 mile 
north of Fork Union, and is about 3 miles northeast of Fork Union station 
on the Virginia Air Line Railway. 

History .—According to Credner the mine was first opened in 1838 and 
worked for nine months, during which time it yielded $6,000. c The ore 
was treated in a primitive stamp mill operated by water-power, and much 
of the gold is said to have been lost in the tailings. Hamilton states that 
the mine was worked until 1850. d The vein was opened by a shaft 25 
feet deep, several open cuts along the outcrop, and a tunnel. An attempt 
to reopen the mine was made after the close of the war, and in 1881 the 
chlorination process of extraction was tried.® Xo work has been carried 
on for many years and the old workings are caved and inaccessible. 

Geology .—The vein is located very close to the contact between the 
sedimentary rocks and the granite. On the west side of the vein near the 


«Credner, H., Op. cit. 

^Credner, H., Op. cit. 
cCredner, H., Op. cit., p. 58. 

^Hamilton, J. R., The Natural Mineral Wealth of Virginia, Harper’s Magazine, 
1865, vol. xxxii, pp. 32-42. 

eHotchkiss, Jed., The Tellurium Mine and Virginia Gold Mining, The Virginias, 
1881, vol. ii, p. 85. 



THE GOLD MINES OF THE DISTRICT. 


181 


branch that flows through the property, knotted schists are exposed that 
are identical with those in the bluffs at New Canton. The rock is bluish- 
gray, fine-grained, and contains pseudophenocrysts of garnet and biotite 
1 to 1.5 mm. in diameter. 

The granite on the east side of the vein is a medium-grained gneissic 
rock composed for the most part of feldspar and quartz, white to light gray 
in color, with large black blotches of biotite in small flakes. Under the 
microscope the soda-lime feldspars (oligoclase) are seen to be dominant over 
the potash feldspars (chiefly orthoclase). Some microperthite is present. 
Quartz occurs in irregular grains showing slight optical distortion and 
contains fluid-filled cavities, zircon, and rutile needles. The biotite is 
greenish-brown in color and shows strong absorption. Tourmaline occurs 
in occasional light brown prisms. Much carbonate, a little chlorite, and 
epidote are present as secondary minerals. 

The vein is 3 to 6 feet wide and runs in a northeast-southwest direction, 
the dip being about 65° toward the east. Credner states that the vein 
consists of hard white quartz, “containing sulphurets of iron, copper, lead, 
and zinc, and also oxide of iron, phosphate of lead, carbonate of copper 
and free gold.”" Hamilton mentions the presence of argentiferous galena. 

The Hughes Mine. 

Location .—The Hughes mine comprises a tract of 275 acres located in 
Fluvanna County on the Virginia Air Line Railway about 2 miles north¬ 
east of Fork Union station and 2 y 2 miles southwest of Carysbrook. 

History .—This mine was first opened in 1836, but for many years it 
changed hands frequently and very little development work was done. The 
last period of operation began about 1895 and continued until the spring 
of 1906, since which time the mine has remained idle. During this period 
the mine was developed by the Hughes Gold Mining and Milling Company 
to a depth of 115 feet, and an elaborate plant installed to treat the ore. 

Equipment .—The surface equipment consisted of a double cylinder 
steam hoist at each of the 2 shafts, a boiler house, mill, and cyanide plant. 
The mill building contained 2 batteries of 5 stamps each, amalgamated 
copper plates, and 4 Frue concentrators. The concentrates which carried 
60 per cent, of the values were roasted and the gold extracted by treatment 
with cyanide solutions, while the tailings from the stamp mill were cyanided 
raw. The extraction is said to have been over 90 per cent, and the cost 


oCredner, H., Op. cit. 


7 



182 GEOLOGY OF THE GOLD BELT IN' THE JAMES RIVER EASIN. 

of mining and milling a little over $4.00 per ton. At present the mill is 
partly dismantled and some of the machinery has been removed. 

Underground development arid description of veins. —According to 
Mr. Bugbee, who was general manager for the Hughes Gold Mining and 
Milling Company, the underground development work has been limited 
to 3 veins, two of which strike in a northeast-southwest direction parallel 
to the country rock, while the third running in an east-west direction cuts 
across the rock formations and intersects one of the other veins. The 
figures given below were taken from a prospectus issued by the Hughes 
Gold Mining and Milling Company in 1905. 

Shaft Ho. 1 was sunk to a depth of 40 feet on the larger vein, a level 
was driven from the bottom of the shaft 140 feet southwest along the vein, 
and more than 50 feet of ore above this level has been stoped and milled. 
A mill run on 585 tons of this ore is said to have given a gross value of 
$9.00 per ton. The vein has been proved by surface pits for 1,500 feet 
along the strike and has an average width of 2% feet. 

Shaft Ho. 2 was sunk to a depth of 110 feet on a second vein about 
800 feet southwest of the first, and levels were driven at depths of 60 
and 110 feet, respectively. From these levels cross-cuts were driven to 
reach the third vein 128 feet from the shaft. The second vein has been 
stoped out from the 60-foot level to the surface. It averaged l 1 /^ feet in 
thickness between the extremes of 1 and 3 feet, and the average value is 
given at $20.00 per ton. The third vein, which has been developed for 
230 feet along its strike, varies from 1 to 4 feet in width, averaging 2 feet, 
and is said to be worth $13.00 per ton. In addition to the veins mentioned 
above 4 other veins have been prospected by surface pits and found to 
contain good values in gold. 

Geology of veins and country rock. —At the time this property was 
visited the underground workings were filled with water and therefore 
inaccessible, so that it was not possible to examine the veins and wall rock 
in place. The ore found on the surface is chiefly vein quartz, varying from 
coarsely crystalline to saccharoidal in texture, and in places it contains 
much pyrite. Fine flakes of light green chlorite are frequently present in 
the quartz chiefly along fractures, and chloritic schist containing pyrite 
was found attached to some of the ore. 

The wall rock, as indicated by material found on the shaft dumps, is 
a greenstone schist derived from an igneous rock, probably a diorite 
porphyry. In the hand specimen it varies from light to dark green and 
contains eyes of light blue opalescent quartz, ranging up to 0.5 cm. and 


THE GOLD MINES OF THE DISTRICT. 


183 


over in diameter. In thin section (Spec. 36) a the large quartz eyes show 
optical distortion and some granulation. Rutile needles are occasionally 
present as inclusions. The ground-mass is composed of soda-lime feldspars, 
quartz, chlorite, epidote, zoisite, sericite, and a little titanite. The min¬ 
erals show the effects of mashing, and the feldspars are extensively altered 
to saussurite and chlorite. 

With the exception of the veins belonging to the Gold Hill system, this 
is the only mine in the district where gold-bearing veins have been found 
in rock of igneous origin. A short distance west of the veins ferruginous 
quartzites occur which are similar to those found interbedded with the 
schists in many localities throughout the area. At several places on the 
property pieces of almost pure magnetic iron ore are present on the 
surface, and some specimens 6 were seen which have the appearance of a 
hematite breccia recemented with magnetite and hematite. The magnetite 
occurs in masses that are composed of small grains and octahedral crystals 
ranging up to 2 mm. in diameter. 

MINES IN BUCKINGHAM COUNTY. 

The London and Virginia Mine. 

Location .—The London and Virginia mine, or London mine as it is 
sometimes called, is located about a mile north of Dillwyn, a station on 
the Buckingham Branch of the Chesapeake and Ohio Railway. It joins 
the property of the Buckingham mine on the southwest. 

History .— 1 This property was first known as the Eldridge mine, and it 
was worked for a number of years by Mr. Eldridge before being sold to 
the London and Virginia Gold and Copper Mining Company, which was 
formed in London and incorporated in Virginia in 1853.° 

At first most of the ore was derived from open cuts, which were carried 
to a depth of 20 to 40 feet, and extended for a distance of 150 yards along 
the outcrop. Later, shafts were sunk proving the vein to a depth of at 
least 150 feet, and underground mining was extensively carried on. Oper¬ 
ations were being conducted at the same time on the adjoining property, 
known as the Buckingham mine, and the two mines were connected under¬ 
ground by a continuous drive along the vein. 

The mill used by Mr. Eldridge to pulverize the ores was located some 
distance north of the mine and operated by water-power. This mill was 

aThis thin section was made from a specimen collected by Dr. J. S. Grastv. 

^Specimens collected by the State Geologist, Dr. Thomas L. Watson. 

cWhitney, J. D., The Metallic Wealth of the United States, Philadelphia, 1854, 

p. 128 . 



184 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


in operation for about 15 years, and Mr. Partz, in 1854, stated that there 
were at least 200,000 bushels of tailings lying on the ground, which could 
be advantageously worked over a second time.® Later a mill was built a 
few hundred yards southeast of the vein, and the pile of tailings, which 
remains to this day, is mute evidence of an industry long since suspended. 
The property was closed down 5 or 6 years before the Civil War, and since 
that date active mining has not been resumed, but it is said that the old 
piles of tailings have been reworked at a profit, and $10,000 extracted 
from them. 

Descriptive geology .—The London and Virginia “vein,” or “bed” as it 
has been variously called, has been opened up for practically the entire 
distance across the adjoining properties of the London and Virginia and 
the Buckingham mines, and there are numerous shafts and pits located 
along its line of strike for a distance of several miles. Since the greatest 
amount of development work has been done on the two properties above 
mentioned, and since the character of the ore and the structural relations 
of the enclosing country rocks are essentially identical wherever they have 
been observed; a single detailed description will suffice for both the London 
and Virginia and the Buckingham mines, and in the case of other 
properties located along the same vein only the variations from this 
description will be noted. 

The London and Virginia vein is situated in a series of fine-grained 
schists and schistose quartzites, all of which are probably sedimentary in 
origin. The formation has an average strike of N. 40° E. and dips at a 
steep angle toward the southeast, in places being practically vertical. 
While there are few outcrops in the vicinity of the mines, the material on 
the dumps and the rocks exposed in the open cuts, which are almost con¬ 
tinuous along the outcrop, together with the descriptions of the mines by 
Ansted, Henwood, and others, who examined them when they were 
accessible, furnish sufficient facts to make possible the drawing of general 
conclusions in regard to the character of the ore, and the relation of the 
ore deposit to the surrounding rocks. 

Kenwood states that “a rather fissile and somewhat contorted clay- 
slate, of homogeneous texture and leaden hue—the lowest rock observed 
in the neighborhood—is succeeded by a narrow band of whitish quartzose 
mica-slate, frequently interspersed with talc [probably sericite] ; the 
auriferous deposit which succeeds is overlaid by thin lamellar greenish- 
white chloritic talc-slate [sericite-schist] now and then flecked with mica.” 6 


aPartz, A.. Examinations and Explorations on the Gold-Bearing Belts of the 
Atlantic States, Mining Magazine, 1854, vol. ii, p. 380. 

bHemvood, W. J., Observations on Metalliferous Deposits, Trans. Royal Geol. 
Soc. of Cornwall, 1871, vol. via, p. 37G. 



THE GOLD MIXES OF THE DISTRICT. 


185 



Quartzite 


Quo'tz Sefcte 

Schist 


Maqnetito 

deormg Schist 


ChlontiC Schist 


D'Obase 


SCALE 

o X l A 


1 Mile 


Fig. 17.—Sketch of map showing surface geology and location of mines and pros¬ 
pects along the strike of the London and Virginia vein, in the vicinity of Dillwyn. 


A rock (Spec. 340) probably corresponding to the lead-colored slate 
mentioned above was found by the writer at the Buckingham mine, on 
the dump of a small pit which is located on the west side of the road 
crossing the property, and about 100 yards northeast of the outcrop of the 
vein. This rock is a chloritic schist varying somewhat in granularity but 


































































































































































































































186 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

usually fine-grained. The dominant type is a dark gray schist in which 
most of the minerals are too fine for megascopic identification. It is cut 
by frequent fracture lines along which a little epidotization has taken 
place. Sericite, quartz, and chlorite can be identified with the aid of a 
pocket lens, and the rock contains much fine-grained magnetite, a little 
pyrite, and is closely sprinkled with small pink garnets, less than 0.5 mm. 
in diameter. 

Apparently the same chloritic schist as that just described crosses the 
road 125 yards northeast of Shepherd’s Crossroads. While much weathered 
at this point the rock does not appear to be more than 50 or 60 yards wide. 
Northwest of this bed no exposures were found but the residual decay 
indicates that, for some distance, the country rock is for the most part a 
light-colored quartz sericite schist. 

About 50 yards southeast of the rock described above, and 50 yards 
northwest from the outcrop of the vein, there is an old shaft or pit, now 
caved, but the dump contains some comparatively fresh rock (Spec. 341). 
It is a very fine-grained quartz-sericite schist, pure white in color, which 
breaks readily along the cleavage planes, exhibiting a bright lustrous 
surface due to minute flakes of sericite. The rock is cut in two or more 
directions by closely spaced joints that cut the planes of schistosity at an 
oblique angle. A few grains of opalescent quartz, 0.75 mm. in diameter, 
and very fine grains of pyrite are the only minerals that can be distin¬ 
guished megascopically. 

In thin section under the microscope the rock is seen to consist largely 
of small quartz grains, the spaces between them being filled with a clear 
colorless mineral without cleavage and having a much lower index of re¬ 
fraction than the quartz (probably albite or orthoclase feldspar). Small 
flakes of sericite occur, mostly segregated in separate bands. There are 
also narrow bands or veinlets of quartz, slightly coarser grained than the 
rest of the rock, and the frequent association of these with pyrite suggests 
that they may in part be due to the circulation of solutions, rather than 
to recrystallization without migration of the mineral particles. Gas- and 
liquid-filled cavities are present in the larger quartz individuals. The 
pyrite ranges up to 0.2 mm. or over in diameter, but most of it is much 
finer. A little titanite is present in small grains. 

The quartz-sericite schist by decrease of sericite passes into a fine¬ 
grained schistose quartzite, which usually carries more or less sericite. 
In places the change from schist to quartzite is quite sharp, but the fact 
that the two rocks are contemporaneous and have had a similar origin 


THE GOLD MINES OF THE DISTRICT. 


1ST 


can not be doubted. In the vicinity of the vein both the quartzite and 
schist are heavily impregnated with pyrite. 

West of the vein, the rocks in places contain much magnetite. Some 
of the quartzite carries fine-grained magnetite and hematite, and on the 
surface, near the outcrop of the vein, pieces of biotite schist were found 
which contained numerous well-formed octahedra of magnetite. This rock 
is fine-grained, dark gray to black in color, and is composed for the most 
part of biotite, quartz, numerous reddish-brown garnets, and, in places, 
much magnetite in perfect octahedral crystals about 1 mm. in diameter. 
In the different laminae the proportion of these minerals varies somewhat 
and a little sericite may also be present. The rock is cut by a number 
of bands or veinlets of fine-grained quartz, which are usually parallel to 
the schistosity. 

Southeast of Shepherd’s Crossroads 150 yards, a fine-grained sericite 
schist outcrops in the road. It has a strike of 1ST. 40° E. and dips steeply 
to the southeast. The rock is composed essentially of fine-grained white 
sericite with little if any quartz, and contains numerous small iron-stained 
cavities left by the oxidation and removal of pyrite or magnetite. For a 
distance of several hundred yards southeast of this point, while there are 
no exposures, much magnetite is concentrated on the surface, and it has 
probably weathered out from magnetite-bearing schists essentially similar 
to those already mentioned. 

About 100 yards northwest of the vein, where it outcrops at the Buck¬ 
ingham mine, a diabase dike about 75 feet wide crosses the road in a 
northeast-southwest direction, but could not be traced for any great distance 
along the strike. A short distance west of the road a small pit furnishes 
exposures of the fresh rock. It is a coarse-grained, olivine-bearing rock, 
with marked ophitic texture. The feldspars are 3 to 4 mm. long and 
twinning is easily detected with the naked eye. It is unlikely that this 
rock has in any way influenced the ore deposits. 

Description of vein .—Since most of the vein exposures have been 
rendered inaccessible through the caving of old workings it is not now 
possible to examine the ore-body in detail, but Henwood gives the follow¬ 
ing description: 

“The metalliferous bed, conforming to the dissimilar flexures of the 
rocks on opposite sides, varies in width from 3 to 20 feet on the northeast, 
but 4 to 5 only toward the southwest. The northeastern portion consists, 
near the surface, of granular, massive, and cellular quartz; sometimes 
embedded in, but frequently mingled with, earthy brown iron ore. Traces 
of galena occur at intervals; and small drusy cavities often afford crystals 


188 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

of the phosphate of lead and of selenite. The quartzose parts contain 
bodies of friable iron pyrites; of which the most deeply seated are the 
largest and most numerous. These . . . enclose isolated masses of 

copper-pyrites; invested occasionally with copper-glance, but more gen¬ 
erally with earthy black copper ore. a The southwestern portions include 
many unconnected, angular blocks of slate; of all which the composition 
resemble, and the planes of structure conform to, the compositions and 
structures of the rocks in their respective neighborhoods. Except in this 
particular, and that massive quartz is more abundant, the southwestern 
parts differ but little from the northeastern. . . . The earthy brown 

iron ore and the quartz are slightly auriferous when separate; but when 
united in certain manners and proportions—more easily recognized than 
described—they frequently enclose small nuggets, thin plates, and 
crystalline grains, united by threads of gold; which constitute from 
0.0000056 to 0.0000070 of the ore extracted.” 6 

According to Partz the oxidized or “soft ores” extended to a depth of 
20 to 40 feet “where the slate became hard and solid on account of the 
undecomposed auriferous pyrites in it”; c and Ansted states that “about 
80 feet down from the surface threads of copper ore were found consisting 
of copper pyrites mingled with iron pyrites which forms the staple.”^ 

The sides of the old open cuts from which the ore was taken frequently 
furnish exposures of dark iron-stained quartzite, usually containing small 
cavities due to the removal of pyrite. At the Buckingham mine a large 
mass of this quartzite remains standing in the center of the opening, ore 
having been removed from either side, and the walls of the cut are of the 
same material. Where the surface has not been disturbed there are in 
places outcrops of quartzite in line of strike with the old workings. 

The ore found on the dumps and in the vicinity of the mine which 
came from the deeper workings is mostly fine-grained, white quartzite with 
more or less disseminated pyrite. White quartz-sericite schist similarly 
impregnated with pyrite also occurs, but does not appear to be as plentiful 
at the Buckingham and London and Virginia mines, as at some other 
localities along the strike of the vein. 


“The following note is given by Henwood on page 376 of the publication 
previously cited: 

“This ore afforded 0.230000 its weight of copper 
0.001142 its weight of silver 
0.000060 its weight of gold 

Johnson and Matthey, Prospectus of the London and Virginia Company, p. 2.” 
bHenwood, W. J.. Op. cit., pp. 376 and 379. 
cPartz, A.. Op. cit., p. 379. 

JAnsted, D. T., The Alleghanies and the Gold District of Eastern Virginia in 
Scenery, Science and Art, London, 1854, p. 287. 



THE GOLD MIXES OF THE DISTRICT. 


189 


A specimen (342) found on the dump at the Buckingham mine shows 
the quartzite in contact with the quartz-sericite schist. The quartzite is a 
white, fine-grained, even-granular rock, impregnated with fine crystals of 
pyrite; and a little sericite in minute flakes can be distinguished on 
fracture surfaces approximately parallel to the schistosity. The schist is 
composed of the same minerals as the quartzite, the difference being in 
their relative proportions; sericite is very prominent, though in this 
specimen quartz is probably the dominant mineral, and pyrite is more 
abundant than in the quartzite. The contact between the two rock types 
while slightly irregular is quite sharp, and makes an angle of about 40° 
with the schistosity of the rock. The pyrite is uniformly disseminated, 
except that it is more plentiful in the schist than in the quartzite, making 
up perhaps 10 or 13 per cent, of the former and not more than 4 or 5 per 
cent, of the latter. 

In thin section under the microscope the quartzite is seen to be com¬ 
posed of small clear, interlocking grains of quartz showing no optical 
distortion, idiomorphic crystals of pyrite ranging from dust-like particles 
up to crystals 1 mm. in diameter, and a few flakes of sericite. Occasional 
scattered crystals of orthoclase and acid plagioclase may be observed, and 
in places interstitial space between the quartz grains contains a light brown 
or colorless to cloudy mineral which is isotropic, and has a low index of 
refraction. It is probably some variety of opal. The quartzite has un¬ 
doubtedly undergone extensive recrystallization, and the pyrite which 
impregnates the rock is probably secondary, replacing some of the quartz. 

Only a very little massive vein quartz can be seen on the dumps, but 
several pieces of quartzite were found cut by small veinlets of massive 
quartz, ranging up to several inches in thickness. One specimen (343) 
shows a vein of massive quartz, 2 to 4 inches wide, which contains feldspar, 
nearly white in color with a slightly pinkish cast, and difficult to distin¬ 
guish at a glance from the quartz. The feldspars occur partly in single 
individuals 1 to 2 mm. in diameter and partly in clusters having an area of 
2 cm. or more. Occasionally coarse multiple twinning can be distinguished 
with the naked eye. The quartzite and schist in contact with these veinlets 
are heavily impregnated with pyrite, but the vein quartz contains com¬ 
paratively little of this mineral. 

In addition to the minerals mentioned in the above descriptions, several 
others have been reported by various writers. Partz states that “in one 
pit we found several specimens of fibrous (asbestiform) actinolite. . . . 

Specular ore of a great variety, in form and color, is frequently met with. 


190 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


There were shown to us pretty specimens of heavy spar (sulphate of 
barytes) and talcite, taken also from these mines/’® 

Genth found a mineral associated with quartz and auriferous pyrite in 
ore from the London and Virginia mine which in composition corresponds 
to tennantite, the analysis being closely similar to that of a specimen from 
the Jucud mines, given by Dana/ The description of the mineral as given 
by Genth is quoted below. 

“In granular masses; lustre metallic; color between iron-black and 
lead-gray; streak iron-black; opaque; Ii. = 4. Very brittle; fracture 
uneven—subconehoidal. 

“B. B. in an open tube disengages sulphurous acid; and gives a 
sublimate of arsenious acid. On charcoal it emits fumes of an alliaceous 
odor, and fuses with intumescence to an iron-black, slightly magnetic 
globule, covering the charcoal with white incrustations. With fluxes it 
gives the reactions of copper and iron.” 

A preliminary analysis, made by dissolving the mineral in aqua regia, 
gave Mr. Wm. J. Taylor the following results : c 

Per cent. 


Copper . 40.64 

Silver . 0.42 

Gold . trace 

Zinc . 3.39 

Iron . 4.24 

Antimony . 5.10 

Arsenic . 16.99 

Sulphur . 28.46 

Quartz . 1.24 


The Buckingham Mine. 

Location .—The Buckingham mine is situated three-quarters of a mile 
northwest of Dillwyn, and on the northeast it joins the property of the 
London and Virginia, both being located on the same vein. 

History .—In some of the earliest descriptions of this property it is 
referred to as the Wiseman mine. The Buckingham Gold Mining Company 
was organized to operate the property in 1853, and proceeded to develop 
the mine on a larger scale/ The earliest work was limited to open cut 
mining and the surface openings were carried to a depth of 20 to 40 feet. 
Later 2 shafts were sunk and levels were driven to some extent along the 

f'Partz, A., Op. cit., p. 379. 

bDana, E. S., A System of Mineralogy, 6th ed., New York, 1892, p. 140. 
cGenth, F. A., Contributions to Mineralogy, Amer. Jour. Sci., 2d ser., 1855, 
vol. xix, pp. 18-19. 

JWhitney, J. D., The Metallic Wealth of the United States, Philadelphia, 1854, 

p. 128. 












THE GOLD MINES OF THE DISTRICT- 


101 


vein, connecting through with the underground workings of the London 
and Virginia mine. The deepest shaft is said to have reached 180 feet, 
but practically all the ore mined came from the upper portions of the vein. 
It seems probable that two or more mills have been operated on the 
property, but the principal mill was located near the branch some distance 
northeast of the mine. The pile of tailings still in existence indicates that 
much ore was milled here. Austin writing in 1854 states that an average 
of 20 tons of ore were being crushed daily, yielding 130 dwt. of gold per 
day, and that during the previous year 1,500 ounces of gold were obtained 
from the mine. Mining operations ceased several years before the out¬ 
break of the Civil War and have not been resumed since that date. At 
present the shafts and underground workings are all caved, while the 
mills were destroyed years ago. 

One of the most noticeable features both at the Buckingham and the 
London and Virginia mines is the absence of large dumps of waste rock. 
Practically all the material taken from the mines appears to have been 
put through the mills. 

Geology of the ore-body .—As the character of the ore and the geology 
of the deposit have already been referred to in describing the London 
and Virginia mine (see pp. 184-190) they will not be repeated here. 

The Williams Mine. 

Location .—The Williams mine is located at Shepherd’s Crossroads 
about a mile northwest of Dillwyn. It is less than three-quarters of a 
mile southwest of the principal workings at the Buckingham mine, and 
lies directly on the same line of strike (see map, p. 185). 

Description .—There are several old prospect pits in this vicinity and 
recently a shaft has been sunk to a depth of perhaps 50 feet. The dump 
is covered with white quartz-sericite schist impregnated with pyrite and 
is similar to that at the Buckingham mine already described. Only a very 
few small fragments of vein quartz are to be seen, indicating the presence 
of occasional veinlets, mostly less than an inch in thickness. Pieces of 
this quartz sometimes contain a little pyrite, chiefly along their edges. 
The recent work is said to have been done with the hope of developing a 
pyrite mine. Some of the material on the dump carries as high as 80 or 85 
per cent, pyrite. A thin section of this high-grade ore (Spec. 344) when 
examined under the microscope was found to consist of more or less idio- 
morphic crystals of pyrite, sericite, a few small grains of titanite, and 
little or no quartz. The pyrite seems to have replaced quartz in the sericite 


192 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

schist in preference to the other minerals, chiefly sericite, the latter being 
affected little if at all. 

Passing southwest along the strike of the London and Virginia vein, 
old prospect pits, trenches, and a few shafts are found at short intervals 
for a distance of 10 or more miles, until the Bondurant mine is reached a 
short distance southwest of Andersonville. Most of this work was done 
over 50 years ago, and to-day the dumps are for the most part reduced to 
soil and overgrown with trees and bushes, so that there is very little to 
indicate the character of the material that was removed from the openings. 
The few written records of this early work confirm the data collected in 
the field, and indicate that the bed of quartzite, which where mineralized 
forms the greater part of the ore-body at the London and Virginia and 
Buckingham mines, is practically continuous throughout most of this 
distance. The quartzite varies somewhat in width and degree of mineral¬ 
ization, but is remarkably uniform in texture and appearance wherever 
observed. The outcrops are usually stained with iron and the rock more 
or less porous from the oxidation of pyrite, but in most cases the sulphides 
could not have been so abundant as in the vicinity of the London and 
Virginia, and Buckingham mines. While gold is reported to have been 
found at many of these places, it is improbable that the values anywhere 
along this southern extension of the vein approach those obtained from 
the ores at the London and Virginia, and Buckingham, when these mines 
were being worked. At several of these properties surface washing has 
been attempted, but with little success, and no underground mining has 
been carried on. 

The Bondurant Mine. 

Location .—The Bondurant mine is located about a mile southwest ‘of 
Andersonville and about 10 miles from Dillwyn. 

History .—Placer mining is said to have been conducted on this property 
as early as 1836, and some of the hillsides as well as the branches were 
washed for gold. A few years later it was leased from the owner, Mr. 
Bondurant, by Major Miller, who built a small stamp mill on the branch 
flowing through the property and worked a vein that outcrops on the hill 
about 400 feet to the south. A royalty of a tenth of the gold recovered 
was paid to the owner, and during the period of 10 months in which 
mining was carried on, he is said to have received $240. Credner visited 
the property in 1865 and writes that “two parallel veins, 30 feet distant 
from each other, have been opened by excavations 20 to 25 feet deep, and 
by two shafts, 35 and 45 feet deep, respectively. One of these veins is two 


THE GOLD MINES OF THE DISTRICT. 


193 


feet wide and the other four and a half feet. They stand nearly vertical, 
cross the property for three-quarters of a mile, and carry sandy quartz 
with much oxide of iron and free gold. The ores were crushed in a stamp 
mill and amalgamated in arrastras; but tailings only now mark the place 
where these works stood.”® 

About 1875 a small stamp mill was operated on the property for a 
short time, with what results is not known. In 1901, a tunnel starting 
near the creek was driven southeast for a distance of 410 feet, connecting 
with three shafts having depths of 30, 40, and 71 feet, respectively, and 
from a point near its extremity a drive was opened for 96 feet southwest 
along a vein. Mr. Moore, who had charge of the work at the time, states 
that 5 parallel veins were encountered in the tunnel, the largest being 31 
feet thick while the others ranged from 3 to 8 feet, and that another vein 
was located by a test pit on the opposite side of the creek. He says that 
assays were obtained running as high as $65 per ton, the veins averaging 
$4.50 per ton in gold. 

Descriptive geology .—The few exposures observed in the vicinity of the 
Bondurant mine indicate that the country rocks are similar to those at the 
mines near Dillwyn, which have already been described in detail on pages 
184-187. Quartzite, frequently containing magnetite and specular hematite, 
is the chief rock found on the surface. When the property was visited by the 
writer in 1911 the greater part of the tunnel had been rendered inaccessible 
through caving, but the dump afforded much information concerning the 
character of the rocks. 

The so-called “veins'’ appear to be beds of quartzite, more or less 
mineralized and cut by occasional veinlets or stringers of massive crystalline 
quartz, which frequently contain large crystals of muscovite. A specimen 
(312) of the quartzite cut by small lenses and stringers of vein quartz is 
shown in fig. 18. The quartzite is white when fresh, fine-grained, even- 
granular, and slightly schistose, the schistosity being parallel to the bed¬ 
ding. Looking at a piece that has been fractured across the schistosity, 
the rock appears to consist entirely of quartz with a little fine-grained 
pyrite, but on a fracture parallel to the schistosity, much white, fine, scaly 
sericite is visible. Lenticular eyes and stringers of vein quartz occur 
parallel to the bedding and also cut directly across, as shown in fig. 18. 
Fine-grained pyrite, much of which is in such small particles as to be 
almost invisible to the naked eye, is disseminated through the quartzite, 

«Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 72. 



194 GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIN. 

being somewhat more abundant along the principal bedding planes and in 
close proximity to the veinlets, but the impregnation with sulphides does 
not appear to be nearly so extensive here as at the London and \ irginia, 
and Buckingham mines. 



Fig. 18.—Sketch of specimen showing quartz veinlets cutting across bedding and 
schistosity of quartzite, Bondurant Mine. 

The quartzite is interbedded with a fine-grained quartz-sericite schist, 
containing lenticular eyes of light blue opalescent quartz ranging up to 
0.75 cm. in length. The folia of the schist are wrapped around these eyes 
giving a knotted or bird’s-eye maple like structure to the rock. Pieces of 
quartzite were found on the dump with the schist still adhering, and the 
contact between the two is not perfectly sharp but shows some gradation. 
Another piece of schist contained interbedded layers of quartzite that were 
only a half to an inch in thickness. 

Some of the rock (Spec. 366) found on the dump is intermediate in 
composition between the typical quartz-sericite schist of the district and 
the quartzite. It is a fine-grained, close-textured, light gray schist, with a 
faintly greenish tinge due to microscopic flakes of chlorite and sericite. In 


























































THE GOLD MINES OF THE DISTRICT. 


195 


thin section under the microscope the minerals present, in the order of 
relative abundance, are quartz, pvrite in cubical crystals ranging up to 
about 0.5 mm. in diameter, small flakes of sericite and chlorite, a few 
grains of magnetite, and occasional inclusions of zircon and titanite. 

A little diabase (Spec. 368) was found on the dump. It is a fine¬ 
grained, close-textured, dark gray rock in which no olivine could be 
identified with the aid of a pocket lens. 

The Anderson Mine. 

Location .—The Anderson mine, located about a quarter of a mile south 
of Andersonville postoffice, lies just northeast of the Bondurant mine. 

Description .—The big bed of quartzite opened on the Bondurant can 
also be traced across this property by outcrops and old pits scattered along 
its line of strike. A shaft is said to have been sunk on the property to a 
depth of 50 feet, connecting with a tunnel 70 yards long, but both had 
caved before 1865, and to-day there is little trace of their former existence. 
A little placer washing was done in the branches soon after gold was 
discovered, but that is the extent of the mining operations conducted on 
this property. 

The Flood Mine. 

Location .—The Flood mine lies southwest of the Bondurant and is 
separated from it by Willis River. 

Description .—This property was formerly known as James Anderson’s 
mine, and a little placer washing in the branches is said to have been 
carried on soon after gold was discovered in the district, but with what 
success is not known. A shaft and tunnel were opened prior to the Civil 
War, but they have long since caved, and nothing is now known as to the 
character of the vein exposed. 

The Gilliam Mine. 

The Gilliam mine adjoins the Flood mine and is the most south¬ 
westerly opening on the bed of quartzite, apparently continuous for so 
many miles northeast of the property. Whether it stretches yet further to 
the southwest is not known. According to Credner, who examined the 
property in 1865, when the “vein” was exposed by 7 cuts and a shaft 20 
feet deep, the “vein” is standing vertical and has thinned to a width of 
only 4 feet. He states that the outcrop consists of brown oxide of iron 
with only a little quartz, which indicates that the quartzite is probably 
more heavily impregnated with pyrite than at the Bondurant mine. 


196 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

The Burnett Mine. 

Location .—The Burnett mine is situated on the London and Virginia 
vein about three-quarters of a mile northeast of the London and Virginia 
mine and l 1 /^ miles north of Dillwyn. 

History .—This property was formerly known as the Staples mine, and, 
when visited by Credner in 1865, there was a shaft 54 feet deep exposing 
“a multitude of lenticular quartz concretions in talcose [quartz-sericite] 
slate of bluish color which contain oxide of iron and free gold. The bushel, 
or one hundred pounds of this ore, is worth one dollar.”® The London 
and Virginia vein was not opened on this property until 1881, when the 
Burnett Mining and Milling Co. began development work. A shaft was 
sunk to a depth of 80 or 90 feet and a short tunnel driven from the south¬ 
west along the vein to connect with the shaft. There was another shaft a 
few yards northeast and a number of pits, all of which are now caved. 
The mine was worked during 1881, 1882, and a part of 1883, but has since 
been idle. 

A mill was located 300 to 400 yards west of the mine on the west side 
of a large branch. It consisted of 3 batteries of 4 stamps each. The 
mortar boxes were of cast-iron, while the stamps had square^ wooden 
stems with cast-iron shoes. The mill burned some years ago, but the 
charred stumps of the stems can still be seen standing in the batteries. 
There is quite a large tailings pile below the mill, but it is said that most 
of the ore milled was hauled from the London and Virginia mine. 

Descriptive geology .—The country rock, as indicated by the dump and 
by rock in place in the shaft, is a white, lustrous quartz-sericite schist 
impregnated with fine-grained pyrite, similar in every way to the rock 
occurring on the northwest side of the vein at the Buckingham mine. The 
“vein,” exposed in the shaft, is a bed of quartzite 3 to 4 feet thick, having 
an approximate strike of 1ST. 45° E. and a dip that is vertical or steeply 
inclined toward the southeast. The quartzite is very schistose and con¬ 
tains considerable sericite. In most places near the surface it is colored 
dark brown by the oxidation of pyrite, which has left small cavities in 
the rock. This ore is similar to that at the London and Virginia and the 
vein has been traced from one mine to the other by means of surface cuts, 
outcrops, and float. 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 72. 



THE GOLD MINES OF THE DISTRICT. 


197 


The Hobson Tract. 

The Hobson tract, formerly known as the Morton mine, lies between 
the Burnett mine and the London and Virginia. According to Credner 
a 40-foot shaft was sunk on the London and Virginia vein which here 
attains a width of 10 to 15 feet and exhibits the characteristic appearance 
of the quartzite where the pvrite has been thoroughly oxidized. The vein 
has never been worked to any extent on this property. 

The Morton Mine. 

Location .—The Morton mine is located half a mile west of Johnson, a 
station on the Buckingham Branch of the Chesapeake and Ohio Railway, 
and is about 7 miles northeast of the London and Virginia mine. 

History .—This property was formerly known as the Hobson mine, and 
according to Pollard it was tbe first mine opened in the county. Surface 
washing was carried on in the early days. When the property was visited 
by Credner in 1865 three parallel veins had been opened to a depth of 25 
or 30 feet. He states that they are from 3 to 10 and in some places even 
20 feet wide, and consist of granular massive quartz carrying oxide of iron 
and free gold. One of these veins is said to be the continuation of the 
London and Virginia vein.® In 1906, two shafts, the deepest probably not 
more than 30 feet, were sunk on the property, but there is nothing on the 
dumps to indicate that either one struck a vein. When the writer visited 
the property in 1911 all openings had caved except the last mentioned 
shafts. There is an old dam on the small branch west of the shafts, and 
on the opposite side the ruins of a building, said to have been used in 
washing gold. A little water-worn gravel was found around the building. 

Geology .—The mine is situated in an area of quartzites and schists, 
lying just west of the Arvonia slate belt and in line of strike with the 
London and Virginia mine which is 7 miles southwest. The two shafts 
sunk in 1906 were put down in a quartz porphyry, fresh specimens of 
which were exposed on the dump. 

The rock (Spec. 360) is light gray to nearly white, slightly schistose, 
and is composed for the most part of feldspar and quartz. Occasional 
eyes of light blue to colorless, opalescent quartz, ranging up to 0.75 cm. 
in diameter, are distributed through the rock. A few grains of ilmenite 
and pyrite, and along cleavage planes a little sericite and chlorite make 
up the remaining constituents visible to the naked eye. In thin section 

aCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 58. 



198 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

under the microscope, the, large quartz eyes are seen to be full of small 
zircon crystals, exceedingly minute rutile needles, and gas and liquid inclu¬ 
sions. The potash feldspars (orthoclase and microcline) are dominant 
over the soda-lime feldspar (albite-oligoclase or oligoclase) and ortho¬ 
clase is more abundant than microcline. There is also much mieroperthite 
present in the slide. The minerals show no granulation and little if any 
optical distortion, but the feldspars show some alteration to sericite, and 
to calcite, while the ilmenite is partly altered to leucoxene. 

Between the Morton and the London and Virginia mine, and along 
the same general strike, a number of properties have been prospected by 
means of pits and surface cuts, but no regular mining, aside from placer 
washing, has been conducted on any of them. 

A property, formerly known as the Rough and Ready mine, adjoins 
the Morton mine on the southwest. At some time before the outbreak of 
the Civil War a shaft was sunk on a quartz vein carrying pyrite, and, in 
1879, a pit opened on the property is said to have exposed a vein 6 feet 
in width which showed gold on panning. 

On the Duncan tract, about 1% miles west of Alpha, the gravel deposits 
along the branches were formerly worked for gold and a vein on the 
property was prospected a little but never worked. 

Lying between the London and Virginia and the Duncan properties is 
a tract of land, which at different times has been known as Le Seurs or 
Apperson’s mine, and on it a vein is said to have been explored and some 
ore raised before the war. Later prospecting was renewed, and in 1882 
Campbell writes that 3 veins were exposed. The first, measuring 10 to 15 
feet in width, consisted of a porous siliceous mass containing disseminated 
particles of gold. The second vein, about half a mile east of the first, was 
of whiter quartz but had not been well exposed. The third vein, which 
was still farther to the east, consisted of gold-bearing quartz disseminated 
in hard schistose rock like that at the Morrow mine.® 

The Morrow Mine. 

Location .—The Morrow mine is located about 31/k miles southwest of 
Dillwyn and 2 miles east of Enonville. 

History .—It was one of the first properties in Virginia on which under¬ 
ground mining was attempted and has had a long and varied history. 
When Prof. W. B. Rogers wrote his “Report of the Geological Recon- 

«Campbell, J. L., The Virginia Gold Belt near the Richmond and Alleghanv 
R. R., The Virginias, 1882, vol. iii, p. 120. 



THE GOLD MINES OF THE DISTRICT. 


199 


noissance of the State of Virginia, 1835,” Booker’s mine, as it was then 
called, was already in active process of development. In its early history 
the property consisted of 2 separate mines on the same vein within 100 
yards of each other, which were worked by W. M. Moseley and Co., and 
the Garnett Mining Co., respectively; but in 1852 they were consolidated 
under one management and incorporated under an act of the Virginia 
Legislature. For several years after this the property was controlled by 
an English company. In the early writings on geology and mining, the 
workings were usually referred to as the Garnett and Moseley mines, or the 
Booker mine, but since about 1880, when it was worked for a few years 
by the Morrow Mining Co., it has been known as the Morrow mine. 

Several mills have been built on the property and much money has 
been wasted through the installation of expensive machinery, which after 
little or no use was pulled out to make room for later inventions. While 
the Garnett and Moseley mines were being worked separately there were 
two small mills in operation. In 1854, soon after the English company 
had bought the mine, Mr. Partz® states that a new mill with 72 stamps 
was in operation, replacing the 24 stamps that had previously been em¬ 
ployed, and that the amalgamation was performed on two sets of shaking 
tables. When Credner visited the district in 1865 the mines were shut 
down, but he describes two mills he found on the property; one contain¬ 
ing 4 shaking tables, nearly new, and a very large ball-crusher which had 
not been used; the other with 12 batteries of 3 stamps each, 72 shaking 
tables, arranged in 2 systems, and Chilian mills. 6 In later years, a How¬ 
land mill, consisting of a flat circular disk revolving in an iron shell, was 
used to pulverize the ore, and the sulphides were concentrated on 2 
vanners. An attempt was made in 1893-4 to treat the sulphides by the 
Mears chlorination process, but it is said to have failed because of mechan¬ 
ical defects in the process used, though a satisfactory extraction of the 
gold was obtained.® In 1911 there was no mill on the property. 

Production .—Because of lack of records it is not possible to state the 
total amount of gold produced by this property. A prospectus of the 
Garnet Gold Mining Co., printed in 1852, gives the production of both 
mines for the previous year as follows: 


United States Mint receipts for gold.$25,007.53 

Gold on hand and ore reserved as specimens. . . 1,500.00 

Total .$26,507.53 


oPartz, A., Examinations and Explorations on the Gold-Bearing Belts of the 
Atlantic States, Mng. Mag., 1854, vol. ii, p. 378. 

fcCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1868, vol. vi, p. 393. 

cFroehling and Robertson, A Hand-Book on the Minerals and Mineral Resources 
of Virginia, 1904, p. 48. 






200 


GEOLOGY OF THE GOLD BELT IX THE JAMES FIVER BASIX. 


Mr. W. J. Henwoocl gives the amount of gold derived from both mines 
for the years 1850-2 inclusive : a 


Annual production of gold in pounds Troy. 


Year 

Garnet mine. 

Moseley mine. 

1850 . 


07.92 

1851 . 

36.75 

71.74 

1852 (8 months) . 

20.17 

31.19 


Over $60,000 is said to have been recovered from the placer washings near 
the veins. 

Underground development. —Before underground work was resorted 
to, most of the upper portion of the Booker vein was removed by open-cut 
surface mining down to a depth of 30 feet, and for a distance of over 400 
yards along the outcrop. By 1853, it is said that 5 shafts used for hoist¬ 
ing, ventilation, and pumping had been sunk to an average depth of 100 
feet, and connected by drives 350 feet in length. The vein had been proved 
for over half a mile b}^ 4 or 5 shafts 30 to 50 feet deep, and by as many 
as 50 surface cuts. 6 Later development work extended the underground 
workings, and a good deal of stoping was done, but none of the shafts 
seem to have been carried below 115 feet. When the property was visited 
in the summer of 1911, the openings had partly caved and none of them 
was accessible. 

Descriptive geology.—' The Morrow mine is situated in an area of 
intensely metamorphosed schists and gneisses, which, for the most part, 
are probably derived from sedimentary rocks. At Tongue Quarter Creek 
about a mile southwest of the mine there is a large area of fine-grained, 
dark green, hornblende schists, and 2 miles southwest of the property are 
the bold outcrops of cyanite schist and quartzite that form Willis 
Mountain. 

In the immediate vicinity of the mine there are few rock exposures, 
but the old shaft dumps furnish much information concerning the char¬ 
acter of the country rock enclosing the ore deposits. These rocks are all 
schistose and usually show more or less banding; they range from light 
to dark gray and green in color, are usually garnetiferous, and frequently 
contain an abundance of calcium-iron carbonate, probably a variety of 
ferrocalcite. The latter mineral is finely crystalline and light brown in 

oHenwood, W. J., Observations on Metalliferous Deposits, Trans. Royal Geol. 
Soc. of Cornwall, 1871, vol. viii, p. 382. 

bThe Garnet and Moseley Mines, Virginia (Reprinted from a paper by “The 
Editor,” in the Richmond Enquirer), Mining Mag., 1853, vol. i, pp. 164-1G7. 













THE GOLD MINES OF THE DISTRICT. 


201 


color when fresh, turning to dark brown on weathering; it effervesces very 
slowly in cold dilute hydrochloric acid, and on heating before the blowpipe 
becomes only slightly magnetic. Wet tests give heavy precipitates of cal¬ 
cium and iron, but little or no magnesium. 

A thin section was made from a light gray, gneissic rock in which the 
carbonate was particularly plentiful. Megascopically the rock (Spec. 378) 
shows imperfect banding of the light- and dark-colored minerals; the 
lighter bands being largely composed of carbonate and quartz, while in the 
dark ones biotite is a prominent constituent. White mica, pink garnets, 
and a few small grains of magnetite and pyrite may also be recognized. 
Under the microscope, carbonate is dominant in the thin section, with 
quartz, sericite, biotite, soda-lime feldspar (andesine ?), and garnet fol¬ 
lowing in the order named. Some of the quartz shows much optical 
distortion, but large clear grains of secondary quartz are also present. 
The feldspars are fresh and clear, and usually show multiple twinning 
after the albite law. The garnets show no suggestion of crystal form, and 
are simply granular aggregates, intermixed with the other minerals, 
principally carbonate. 

There is much light gray schist (Spec. 379) on the dumps, in which 
the principal constituents distinguishable without the aid of the microscope 
are fine-grained quartz, sericite, scattered flakes of biotite, averaging 1 mm. 
in diameter, and occasional eyes of opalescent quartz 5 or 6 mm. in 
diameter. 

Another rock type (Spec. 376) occurring on the dumps, is a dark green 
and reddish-brown gneiss in which most of the minerals (especially mica 
and garnet) are very largely concentrated in narrow bands or lenses. 
Megascopically, the following minerals can be distinguished: Biotite, in 
black flakes 0.5 to 1.5 mm. in diameter, which occur partly in narrow 
bands, the cleavage of the mica being at varying angles with the schistosity 
of the rock; garnet, in irregular lenticular masses 1 cm. or more in thick¬ 
ness; fine flakes of sericite and light green chlorite; quartz; much fine¬ 
grained magnetite; and occasional feldspars, 1 to 1.5 mm. in diameter. 

In thin sections under the microscope, much feldspar can be distin¬ 
guished, partly a soda-lime feldspar with albite twinning, and partly a 
clear feldspar with low index of refraction and no twinning (albite or 
orthoclase). Much of the feldspar and quartz show optical distortion, and 
in places zonal extinction can be observed. In addition to the minerals 
already mentioned, much calcite was noted, and occasional fragments of 
zircon and titanite. Gas- and liquid-filled cavities occur in some of the 
quartz. 


202 GEOLOGY OF THE GOLD BELT IN THE JAMES EIVER BASIN. 

Dark green hornblende is present in part of the schists, and some 
pieces are heavily loaded with the sulphides, pyrite and pyrrhotite. Some 
of the pieces of schist and gneiss contain lenses or stringers of quartz and 
carbonate, usually with a little white mica; and there is a great deal of 
rock (Spec. 373) on one of the dumps, consisting of dark-colored, fine¬ 
grained schists, cut by numerous branching veinlets of quartz and car¬ 
bonate, with some muscovite and light green chlorite. These veinlets 
range up to several inches in thickness, and often make up as much as 50 
per cent, of the rock mass. This material is very similar to some of the 
“vein” stuff described by a number of geologists who have examined the 
underground workings. Thus, Prof. Campbell states that, “the ‘vein/ as 
it is called, in which work was going on [at the time of his visit in 1881 
or 1882], is at least 30 feet wide, and is composed of a schistose rock with 
injected quartz, forming in some places secondary veins and thin sheets, 
and at other points, apparently dispersed, with its accompanying auriferous 
pyrites, in the slaty beds of hard rock that make up the main mass of 
what is taken from the mine.”® 



Fig. 19.—Section across the district worked for gold in the Morrow Mine. (After 
Ansted, Scenery, Science and Art, p. 289.) a, rotten schists with pipe clay; 
b, steatite; c, principal auriferous band called east vein; d, hornblendic rock; 
e, upper auriferous band (west vein) ; f, overlying beds. 

Prof. Ansted describes the “belt” of rocks in which the ore bodies occur 
and gives a geological section showing the structural relations of the rocks 
in their immediate vicinity. (See fig. 19.) His description is as follows: 

“The actual breadth of this belt I had no means of exactly ascertain¬ 
ing, but it certainly exceeds 200 yards, and is probably much greater. It 
is, however, subdivided, including distinct bands of mixed quartz threads 
and rotten red and yellow or greenish schists (a). On these repose bands 
of talcose or chloritic schist, which pass into an imperfect steatite (b), 
occasionally used as a firestone to line furnaces. All these are on the east 
or lower side of the series. In the middle, between the two well-marked 
auriferous bands which next succeed, is a certain thickness of hornblendic 
greenstone ( d ) hard, and tolerably compact. The eastern auriferous band* 
has been extensively worked at the surface.” 6 

flCampbell, J. L., The Virginia Gold Belt near the Richmond and Alleghany 
R. R., The Virginias, 1882, vol. iii, pp. 120-121; Geology and Mineral Resources 
of the James River Valley, New York, 1882, pp. 99-106. 

b Ansted, D. T., Scenery, Science and Art. London, 1854, Chap. 3, The Alleghanies 
and the Gold District of Eastern Virginia, pp. 289-290. 







THE GOLD MIXES OF THE DISTRICT. 


203 


Henwood states that the rocks exposed in the mine contain “mica, talc 
[probably sericite], and chlorite in large but ever-varying proportions,” 
so that one or the other may dominate in laminae only a few inches apart, 
or even in different portions of the same rock layer. 61 

Besides the “principal bed,” Henwood mentions four other “auriferous 
beds,” occurring in and immediately northwest of the mines, which 
“maintain tolerable parallelism; except where they are affected by unequal 
flexures of the adjoining rock; to the schistose structure of which they 
strictly conform.” They vary from 4 to 18 feet in maximum width, but 
average much less, and “within short distances some of them divide, 
dwindle, and die away; occasionally, however, they reappear and again 
enlarge.” 6 

The slates beneath the “principal bed” dip northwest at an angle of 
40° to 60°, but those above preserve the same inclination to a depth of 
60 feet only, and thence downward dip 20° to 30°. As the hanging-wall 
or northwestern side recedes from the foot-wall, and the “auriferous bed” 
between them becomes broader, it encloses lengthwise a wedge-shaped mass 
of slate, which widening downward partakes in some measure of the mineral 
character of the surrounding “vein-stone,” while in structure it coincides 
with the neighboring rocks. c 

According to Prof. Ansted, “the enclosing rock, which within 20 feet 
of the surface is hardly to be distinguished from the vein, gradually 
changes below this point, and within a depth of 10 or 15 feet becomes a 
hard, compact talcose [probably quartz-sericite] schist, often containing 
fine garnets, and not infrequently iron pyrites. In this schist, at a small 
depth, are a multitude of quartz threads, and farther down these threads 
come together, forming a distinct quartz band, often enclosing portions of 
the schist. The gold disseminated indifferently near the surface, amongst 
the quartz, rotten schists and enclosing walls, gradually collects together 
into threads, usually ranging with the schistose portions within the quartz 
band. The walls are very distinctly marked, and easily separated, and are 
found to be no longer auriferous, while the quartz, of which the thickness 
amounts to 10 feet at a depth of about 100 feet from the surface, seems to 
increase continually in value.” 6 * 

The appearance of the vein is shown in the generalized sketch (fig. 20), 
which is drawm from pieces of rock found on the dump, and is in accordance 
with the descriptions of several observers, who have examined the under¬ 
ground workings. 

aHemvood, W. J., Observations on Metalliferous Deposits, Trans. Royal Geol. 
Soc. of Cornwall, 1871, vol. viii, p. 379. 

bibid., p. 380. 

clbid., pp. 380-381. 

(/Ansted, D. T., Op. cit., p. 290. 



204 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 



Fig. 20.—Sketch showing reticulated veinlets with inclusions of wall rock at the 

Morrow Mine. Q, quartz; S, schist. 

Description of ores .—Quartz and schist, varying in relative propor¬ 
tions, always make up the greater part of the ore-body, but Hemvood also 
mentions the presence of small quantities of feldspar scattered through¬ 
out, and in the deeper portions calcareous spar, pyrite, and crystals of 
common garnet. He states that veinlets of quartz, feldspar, and calcareous 
spar cut the metalliferous beds at intervals irrespective of their slightly 
foliated structure, which is generally parallel to the cleavage of the adjoin¬ 
ing strata. Near the surface all parts of the rock-mass contain particles 
and grains of gold but at greater depths, in the “principal bed” flakes, 
granules, nuggets, and threads here and there intertwine the quartz with 
groups of golden filigree. It is stated that tellurium often accompanies 
the gold but is never abundant.® According to Campbell the gold is said 
to carry a considerable percentage of silver. 6 


a Hen wood, W. J., Op. cit„ p. 382. 
^Campbell, Op. eit. 
















THE GOLD MINES OF THE DISTRICT. 


205 


Henwood believes that there is a decrease in values with depth, and 
after calling attention to the gradual decrease in production for the years 
1850-52 (see p. 200), during which time approximately the same number 
of men were employed in extracting the ore, states that, “these results 
show the proportions of gold to have been larger in the shallower and 
narrower, than in the deeper, wider, and flatter parts of the principal bed.” a 

Selected samples are said to have carried 3 oz. 16 dwts. in gold, but ore 
from a depth of 90 feet in the Garnett mine yielded an average of 10.1 
dwt., and from the Moseley mine an average of 8.1 dwt. 6 

Credner says that the gold-bearing beds are cut off by domes and ridges 
of diorite; but the mines were closed at the time of his visit in 1865, and 
he does not give his authority for this statement. 0 

Placers .—During the early history of the property the placer deposits 
were much worked, and over $60,000 is said to have been recovered from 
the gravels near the veins. Henwood quotes Major Miller as writing that 
“a nugget of nearly 9 pounds, besides many masses of a few ounces each 
were mixed with grains of gold in the bed of a rivulet immediately south 
of the Garnett and Moseley mines.” 4 * 

The Seay Mine. 

The Seay property adjoins the Morrow mine on the west, lying between 
it and Enonville, and belongs to the same company. 

The placer gravels were washed for gold and several quartz veins con¬ 
taining pyrite and gold were opened by cuts and small shafts. There was 
a mill on the property before the Civil War, but little mining seems to 
have been done. After the war a shaft is said to have been sunk to a depth 
of 150 feet but nothing further was done. 

The Greeley Mine. 

Location .—The Greeley mine, lying on the headwaters of Hatcher Creek, 
is situated about V -/ 2 miles southeast of Alpha, a station on the Bucking¬ 
ham Branch of the Chesapeake and Ohio Railway, and a mile southwest of 
Gravel Hill. 

History .—The placer deposits at the Greeley mine, formerly known as 
Ayres’ mine, were worked during the early days of gold mining in this 

aHenwood, W. J., Op. cit., pp. 282-283. 

blind., pp. 282-283. 

cCredner, H., Op. cit. 

dHenwood, W. J., Op. cit., p. 384. 



206 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

county, and it is reported the branch gravels yielded much gold. Pros¬ 
pecting has been carried on at various times in the endeavor to locate the 
vein from which the placer gravels derived their gold, and many pits, 
trenches, and shafts have been opened with this object in view, but to-day 
they are all caved. There are several large trenches, leading toward the 
top of a hill, the largest being 30 to 40 feet wide, about the same depth, 
and several hundred feet long in a northeast-southwest direction. While 
these trenches look rather large for the purpose, they are said to have been 
cut while prospecting for the vein. When Credner visited the mine in 
1865 a mill was being started, but it was probably never finished, and 
except for the placer washing no mining has been done on the property. 

Veins and country rode .—Several veins were located by open pits and 
one of them is reported to have carried free gold, but the vein quartz 
exposed when the property was visited by the writer showed little evidence 
of mineralization. 

The lack of outcrops on the property and in its immediate vicinity 
makes it difficult to draw conclusions in regard to the country rock. A 
few pieces of quartz-sericite schist are found on the surface, and at a 
distance of a mile or more northeast and southwest along the strike of the 
formations, schists and quartzites are exposed which apparently belong to 
the same series as the rocks in the bluffs near New Canton. 

One of the shafts is sunk in a gray granitic rock (quartz monzonite) 
which is distinctly schistose. The rock (Spec. 348) is fine-grained and 
even-granular, and a microscopic examination showed it to be composed 
of the following minerals, the order given being that of relative abundance: 
Quartz, biotite, feldspar, hornblende, calcite, garnet, chlorite, magnetite, 
zircon, and tourmaline. The feldspar corresponds to andesine in composi¬ 
tion and shows albite twinning, and orthoclase if present is rare. The 
biotite is dark brown in color with strong absorption. Hornblende occurs 
in light to dark green crystals, with ragged outline, and low interference 
colors. Calcite which is fairly abundant frequently shows multiple 
twinning. The garnets which are light pink in color show ragged outlines 
and contain numerous inclusions of the other minerals. Both biotite and 
hornblende show alteration to chlorite which is dark green in color. 
Magnetite occurs in clusters of small grains and zircon is quite plentiful 
as inclusions. A prism of tourmaline is present in the slide. It is strongly 
pleochroic changing from reddish-brown to dark green. 

Much of the rock is cut by veinlets ranging up to 2 inches or more 
in width, but mostly less than an inch. In places calcite forms one side 


THE GOLD MINES OF THE DISTRICT. 


207 


and quartz the other of a veinlet, but usually they are intermixed, quartz 
occurring in calcite and calcite in quartz. Often the veinlets are much 
contorted, and again they branch and intersect. The contact between the 
rock and the veinlets is not always perfectly sharp but shows a slight 
gradation. Occasionally large crystals of muscovite 4 or 5 cm. in diameter 
are intercrystallized with the quartz and calcite. Where plentiful the 
flakes of muscovite meet one another at all angles, and the interstitial 
space is filled with quartz and calcite. Light-colored pyrite is present in 
the vicinity of some of the veinlets, occurring in cubes 2 to 3 mm. in 
diameter. 

The Lightfoot Mine. 

Location .—The Lightfoot mine is situated on the southeast side of 
Slate River, 2 miles north of Arvonia. 

History .—While this property is now better known as a copper mine 
(see p. 241) it was first worked for gold. It is said that the discovery of 
the mine was due to Geo. Fisher, who worked the property for several 
years under lease. After the expiration of his lease it was worked 
successively by three different companies, who leased it from the proprietor, 
Mr. Lightfoot. The first of these companies is reported to have made 
$300 to $400 per day stamp-milling for gold. The second company con¬ 
fined its work to surface washing, and the last company developed the 
copper deposits, shipping 100 tons of $80-ore to Baltimore, before the mine 
was closed by the outbreak of the war in 1861. Since that time no work 
has been done on the gold veins and at present there is little trace of these 
former operations. In working the placer deposits, gold nuggets worth 
$20 to $30 are said to have been found. 

Gold veins .—The country rock in this vicinity is a greenstone schist, 
which is described in detail on pages 49-51. Credner states that at the time 
of his visit, in 1865, two gold veins were exposed by pits and shafts which 
had partly caved. One of these was 4 feet wide and carried iron sulphide 
and free gold. 

Gold has also been found on the Ford property (see p. 243). 


CHAPTER VI. 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 

INTRODUCTION. 

The genesis of ore deposits has frequently been regarded as a question 
of scientific interest only, but with increasing knowledge of the subject it 
is beginning to be of great practical value from an economic standpoint. 
The unraveling of the structural relations of ore-bodies, particularly in 
regions of extensive faulting, has long been recognized as invaluable to 
the miner, and there is a growing appreciation of the importance of ore 
genesis. A thorough understanding of the mode of formation and of the 
subsequent alterations which may have enriched or impoverished an ore 
deposit, is the only logical basis on which it is possible to predict the 
continuity and character of the ore-body in depth, or to indicate the 
probable location of other deposits that may not be exposed. 

Previous Theories. 

The first geologists to study the gold-bearing veins in this district 
advanced two antagonistic theories to explain the formation and occurrence 
of the ore deposits, and both of these theories have had strong supporters. 
According to one theory, the veins were forcibly injected by igneous 
agencies into older rocks; and since the lines of least resistance were 
usually along planes of bedding and schistosity, the veins, as a rule, con¬ 
formed to the structure of the enclosing formations, although in places 
they split up and cut across. This explanation was advanced and sup¬ 
ported chiefly by Rogers (see page 10). The opposing theory was based 
on the assumption that the ore-bodies were layers or beds deposited 
contemporaneously with the enclosing rocks. This explanation as applied 
to the origin of Virgina gold veins seems to have been advocated first by 
Clemson and Taylor®, and was later supported by Silliman, Ansted, 
Credner, and others. Most of these geologists seem to have ignored the 
fact that some of the veins in places cut across the bedding of the country 
rock, but others, following Ansted, attributed this anomaly to changes 
brought about by “chemical agency” or by a “process of segregation” 
(see p. 11). 

oClemson, T. G., and Taylor, R. C., The Gold Region of Virginia, Trans. Geol. 
Soc. Pa., 1835, vol. i, p. 309. 



GENETIC KELATIOXS OF THE GOLD DEPOSITS. 


209 


The facts established by the present report in many ways support the 
views advocated by Rogers but there are certain important exceptions 
which will be noted later. After examining, at the Tellurium mine, the 
lied of quartzite known as the “Big Sandstone” vein (see pp. 157-164), it is 
easy to understand how the early geologists came to regard the veins as 
sedimentary in origin, for this quartzite is at a glance closely similar to 
the auriferous quartz veinlets which it encloses. 

Types of Deposits. 

The primary gold deposits in this district may be divided into two 
principal types: (1) Veins accompanied by little or no replacement or 
impregnation of the wall rock, and (2) ore-deposits which have been 
formed chiefly through replacement—but there is apparently every grada¬ 
tion between the two extremes. Ores belonging to the first type consist 
essentially of quartz, with more or less feldspar and variable quantities 
of gold. The sulphides, chiefly pyrite, are always present in small 
quantities, but seldom average more than 1 per cent. In the ores belonging 
to the second type, pyrite is the most important constituent and chal- 
copyrite it fairly common. The veins belonging to the Tellurium system, 
particularly the “Middle” vein, may be mentioned as typical examples of 
the first class. The veins at the Young American mine are also of this 
type, for though there has been in places considerable mineralization of 
the wall rock, it is nowhere extensive, and is usually in the nature of 
silicification of the country rock. 

The typical replacement deposits were found only in the southern 
portion of the area in Buckingham County. The London and Virginia 
vein is an example of the latter class, and the Yew Canton ore-body 
probably represents an extreme variety of this type. Under a strictly 
logical treatment of the subject the genesis of the Yew Canton ores should 
probably be considered in this chapter, but because of their localization 
near an igneous contact, their insignificant gold content, and the fact 
that they have been worked chiefly for copper, it has been thought best to 
discuss them elsewhere (see pp. 257-259). 

MINERAL COMPOSITION OF THE VEINS. 

The consideration of minerals associated with gold is important, not 
only because of their possible value as indicators of the presence of the 
precious metal, but also for the reason that such minerals furnish the most 
reliable evidence bearing on the genesis of the ore-deposits. A table, 


210 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

summarizing the minerals which have been found in the gold-bearing 
veins of this district, is given below, together with the names of mines 
where they have been identified, and the authority for each instance cited. 
Both the minerals and the mines are listed in alphabetical order. The 
details in regard to any particular occurrence may be found under the 
description of the mine in chapter V. The table is limited to minerals 
found within the quartz veins, and no attempt has been made to list those 
occurring in the replacement deposits as that would necessarily include 
all minerals present in the wall rock. Common secondary minerals, un¬ 
doubtedly derived from one of the primary minerals listed, are also 
omitted. 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 


211 


List of minerals in the gold veins of the James River basin area, Virginia. 


Name. 

Mine. 

Authority. 

Remarks. 

Gangue Minerals : 




Actinolite .... 

London & Virginia.. 

Partz, 1854.... 

Probably in wall rock. 

Barite . 

Do. 

Do. 

Questionable. 

Biotite . 

Do. 

Bowles. 

Waller. 

This report .. . 

Do. 

Probably derived from in¬ 
clusions of wall rock. 
Along the walls of the 

Do. 

Young American .. .. 

Do. 

vein. 

Probably derived from in- 

Calcite . 

Morrow . 

Henwood, 1871 

elusions of wall rock. 
Probably ferrocalcite. 

Do. 

Waller. 

This report .. . 

Found on the dump. 

Do. 

Young American .... 

Do. 

In vein near wall and 

Chlorite . 

"Rowles. 

Do. 

along the contact. 
Probably from altered in¬ 
clusions of wall rock 

Do. 

Do. 

Hughes . 

Do. 

Do. 

Morrow . 

Do. 

Do. 

Do. 

Scotia . 

Do. 

Do. 

Do. . 

Tellurium . 

Do. 

Do. 

Do. 

Waller. 

Do. 

Do. 

Do. . 

Young American .... 

Do. 

Do. 

Cyanite . 

Young American .... 

Do. 

Do. 

Feldspar . 

Benton . 

Do. 

Kaolinized feldspar in ore 
on dump. 

Do. 

Do. 

Bertha and Edith... 

Do. 

Do. 

Buckingham . 

Do. 

Plagioclase feldspar in 

Do. 

London & Virginia.. 

Do. 

vein quartz on dump. 
Do. 

Do. 

Morrow . 

Henwood, 1871 

With quartz and calcite as 
veinlets. 

Kaolinized feldspar in ore 
on dump. 

Oligoclase-andesine. 

Do. 

Moss 

This report .. . 

Do. 

Do. 

Scotia . 

Do. 

Tellurium . 

Do. 

Do. 

Do. 

Waller . 

Do. 

Albite-oligoclase to oligo- 
clase. 

Dominantly andesine or 

Do. 

Young American .... 

Do. 

Garnet . 

Bowles . 

Do. 

oligoclase-andesine. 
Probably due to inclusion 

Do. 

Morrow . 

Henwood, 1871 

of foot-wall material. 
Do. 

Hornblende .... 

Do. 

This report ... 

Do. 

Do. 

Scotia . 

Do. 

Do. 

Do. 

Waller. 

Do. 

Found on old dump. 

Muscovite 

(including 



Probably chiefly secondary 

sericite) . 

Benton . 

Do. 

Do. 

Bertha and Edith.. . 

Do. 

from feldspars. 

Do. 

Do 

Bondurant . 

Do. 

Do. 

Do 

Bowles. 

Do. 

Do. 

Do 

Buckingham . 

Do. 

Do. 

Do. 

London & Virginia.. 

Do. 

Do. 

Do 

Morrow . 

Do. 

Do. 

Do 

Moss . 

Do. 

Do. 

Do 

Scotia . 

Do. 

Do. 

Do 

Tellurium . 

Do. 

Do. 

Do 

Waller. 

Do. 

Do. 

Do. 

Young American .... 

Do. 

Do. 




































































































212 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


List of minerals in the gold veins of the James River basin area, Virginia — 

( Continued ). 


Name. 


Gangue Minerals : 
( Continued) 

Quartz . 

Selenite . 

Talcite . 

Tourmaline .. . 
Do. 

Do. 


Ore Minerals: 
Clialcocite 
Do. 

Chalcopyrite . 
Do. 


Do. 


Do. 

Do. 

Galena 


Do. 

Gold . 

Ilmenite 

Do. 

Leucoxene 
Magnetite . . 
Do. 

Do. 

Marcasite ( ?) 


Pyrite . 

Pvromorphite 

Do. 

Do. 

Pvrrhotite . 
Sphalerite .. 
Do. 

Do. 

Tellurium 
Do. 

Tennantite 


(?) 


Tetradvmite 


Do. 


Mine. 


All the mines. 

Buckingham or 

London & Virginia 
Buckingham or 

London & Virginia 

Bowles. 

Moss . 


Young American 


Buckingham ) 

London & Virginia f 
Buckingham ) 

London & Virginia ( 


Morrow 


Snead . 

Young American .. .. 
Buckingham { 

London & Virginia \ 


Snead . 

All the mines. 
Scotia . 


Young American . 
Do. 

Bertha and Edith 

Bowles. 

Young American . 
Young American . 


All the mines. 

Buckingham ) 

London & Virginia ( 

Snead . 

Waller. 

Snead . 

Tellurium . 

Young American 

Tellurium . 

Morrow . 

London & Virginia . . 


Tellurium 


Young American 


Authority. 


Remarks. 


Henwood, 1871 

Partz, 1S54 
This report ... 
Do. 

Do. 


Henwood, 1871 

Pprtz, 1854; 
Ansted, 1854; 
Henwood, 1871. 


Partz. 1854. 


Credner. I860. . 
This report .. . 
Credner, 1869; 
Henwood, 1871 

Credner, 1869 


This report 
Do. 

Do. 

Do. 

Do. 

Do. 

Do. 


Henwood, 1871 

Credner, 1869 
This report . 
Credner, 1869 
This report . 
Do. 

Credner, 1869 
Henwood, 1871 
Genth, 1855... 

Fisher, 1849; 
Genth, 1855.. 
This report ... 


Questionable. 

Do. 

Gold Hill vein. 
In vein quartz, 
with pyrite. 
In vein quartz, 


associated 


associated 


with gold and cyanite. 


Description indicates min¬ 
eral is secondary. 


Mentions presence of cop¬ 
per without stating the 
mineral. 


Rare. 

Rare. 

Rare. 

Associated with pyrite. 
“Back Field” vein. 
Associated with pyrite. 

In vug-like opening, proba¬ 
bly left by pyrite. 


Found on old dump. 

Rare. 

Rare. 

Probablv tetradvmite. 

Do. 

Given as tetrahedrite by 
Becker. 

Rare. 

Rare. 




























































GENETIC RELATIONS OF THE GOLD DEPOSITS. 


213 


Description of the Gangue Minerals. 

Quartz is always the most abundant gangue mineral. It varies from 
milky white and translucent to clear and glassy. It is coarsely crystalline, 
in places approaching saccharoidal in texture, and is apparently the same 
wherever it occurs in well-defined veins, lenses, or as a replacement mineral. 
Crystal faces are rare except along joint planes and in cavities left by the 
removal of pyrite, where they are probably due to the enlargement of 
primary individuals by deposition of a little secondary silica. Examined 
microscopically, the quartz frequently shows some optical distortion but 
little or no granulation or other evidence of crushing. The individual 
grains have irregular interlocking boundaries and average from 1 to 3 mm. 
in diameter. Gas- and fluid-filled cavities are common, sometimes occurring 
in irregular branching and interlaced forms, but more often in smaller 
spherical and elliptical shapes, which are usually grouped in rows or planes 
that occasionally extend unbroken from one crystal individual to another. 

Feldspar is the second gangue mineral in relative abundance, having 
been identified in all veins that were well exposed, and in places constitutes 
as much as 10 per cent, of the vein material. It occurs in angular crystals, 
ranging up to 1 cm. or more in diameter, scattered through the quartz, 
but is usually much more plentiful near the walls of the veins. In some 
of the smaller veins, and in places where quartz lenses narrow and pinch 
out (see fig. 14), feldspar is sometimes for a limited distance practically 
the only constituent. When fresh, the feldspars are white to light yellow 
or light pink, and are often difficult to distinguish from the quartz without 
careful examination. In the upper portion of the veins above water level 
the feldspars seem to be entirely kaolinized, but wherever specimens could 
be obtained, sufficiently unaltered for identification by optical methods, 
they proved to be soda-lime plagioclase, ranging from albite-oligoclase to 
andesine. ISTo orthoclase or albite could be distinguished in any of the 
veins. In thin sections under the microscope the feldspars commonly 
show albite twinning but many of them are entirely unstriated. There 
is no evidence of optical distortion, granulation, or other pressure effects. 
In places a little sericite is present as an alteration product of feldspar, 
occurring in clusters of curved and radiating scales, but kaolin is the chief 
secondary mineral. The feldspars are probably of earlier crystallization 
than most of the quartz. 

White potash mica is one of the important gangue minerals, apparently 
occurring in all of the veins. Some of it is in large flakes such as are 
usually called muscovite, while much is in the form of shreds and scales. 


8 


214 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

evidently secondary in origin, and commonly designated as sericite. 
Sericite is a prominent constituent of the wall rocks and is especially 
plentiful in some replacement deposits. 

Biotite and chlorite are frequently present in the veins, but their 
occurrence is such as to suggest that they were chiefly if not entirely 
formed from inclusions of country rock through alteration hy vein-forming 
solutions. The chlorite is partly secondary after biotite and partly derived 
from hornblende; it is doubtful if any of it is an original constituent of 
the veins. Garnet and hornblende rarely occur within the quartz veins 
and where identified were found close to the walls. These four minerals 
are occasionally prominent in the wall rock, and their occurrence and 
distribution indicate that their formation was chiefly due to metamorphic 
agencies accompanying the formation of the veins. 

Black prisms of tourmaline, usually arranged in radiating groups, 
occur in some of the gold-bearing veins, and one specimen was found show¬ 
ing visible gold resting on tourmaline (see p. 131). Tourmaline was seen 
in association with auriferous pyrite, and was also identified in a piece of 
vein quartz containing cyanite. Tourmaline was not noted in any of the 
veins containing much feldspar, and seems to be most plentiful in certain 
bold outcrops of white quartz, which show little evidence of mineralization 
and contain only traces of gold. 

Cyanite was identified in only one of the gold-bearing veins (see pp. 128- 
129), but was found in several quartz veins not known to contain gold. It 
was found in metamorphosed wall rock close to veins under conditions that 
indicate its origin was due to vein action. 

Description of the Ore Minerals. 

Gold occurs chiefly in quartz and mechanically enclosed in pyrite, 
always so far as known in the native state. In the oxidized ores it is 
frequently found in cavities associated with limonite. It was seen in 
small scales, grains, and irregular wire-like masses ranging up to 3 mm. 
in length, and much larger particles have been reported from some veins. 
No evidence of crystal form could be distinguished. Gold was found in 
feldspar and in kaolin derived from feldspar. At the Young American 
mine the presence of chalcopyrite in the ore is considered a favorable 
indication. Gold was identified in association with tetradymite at the 
Young American mine, and at the Tellurium mine it is said to occur 
interfoliated with that mineral. At the former mine gold was found 
resting on tourmaline. 


GENETIC RELATIONS OF TEIE GOLD DEPOSITS. 


215 


Silver is usually present in traces, probably alloyed with the gold. It 
is said to be abundant in some of the ore at the London and Virginia mine, 
and argentiferous galena has been reported at the Page mine. 

Pyrite is the most abundant of the ore minerals and usually carries 
gold values. In veins belonging to the Gold Hill system it occurs in large 
cubes, 1 cm. or more in diameter, but elsewhere it is fine-grained. Cubes 
are the commonest crystal form, pyritohedrons are also present, and 
octahedral faces may occasionally be identified. The pyrite rarely con¬ 
stitutes any considerable proportion of the quartz veins, and where it is 
unusually abundant the gold content is apt to be higher. Occurring as a 
replacement mineral in the schists and quartzite it sometimes forms 90 
per cent, or more of the rock mass. At the Moss mine it occurs asso¬ 
ciated with tourmaline. Limonite is the common alteration product, and 
in places magnetite is associated with the pyrite in such way as to suggest 
its possible formation through partial oxidation of the sulphide. Un¬ 
stained quartz from the Gold Hill veins frequently contains large cubical 
cavities from which pyrite has been wholly or partly removed. This 
phenomenon may be due to solution by ferric solutions or sulphuric acid 
instead of direct oxidation. Secondary sulphides occur along joint planes 
in some of the lowest workings. 

Pvrrhotite is not common and occurs chieflv in altered wall rock close 
«/ «/ 

to the veins. Chalcopyrite is the most abundant sulphide after pyrite, but 
is not an important constituent except in the replacement deposits, and 
there it is largely secondary, occurring chiefly in zones of enrichment near 
water level. Chalcocite has been identified only in replacement deposits 
and is probably all secondary. Galena and sphalerite are both rare. 

Tetradymite, a telluride of bismuth, is sparingly present at two of the 
mines, and the failure to identify it elsewhere is probably due to the lack 
of sufficient exposures as much as to its rarity. While always occurring in 
small quantities this mineral has been identified at many gold mines in 
the eastern gold belt, and seems to be one of the distinctive minerals. 

Manganese minerals were not recognized in the unaltered ores below 
water level, but in the oxidized zone near the surface black stain (probably 
psilomelane) is common along joint planes and fractures. 

Summary. 

A number of the vein-forming minerals are of rare occurrence in gold- 
bearing deposits, and cyanite and soda-lime feldspar have not previously 
been reported. The character and association of many of the minerals are 


216 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN'. 

indicative of deep-seated origin, under conditions of great pressure and 
high temperature. The presence of soda-lime feldspars in gold-quartz 
veins is of considerable importance because of its bearing on the theories 
of ore genesis. The occurrence of these feldspars as primary constituents 
in rocks has been considered the strongest evidence of igneous origin. 

GENESIS OF THE DEPOSITS. 

In presenting the data contained in the previous sections of this report, 
it has been assumed that the ores were deposited from aqueous solutions. 
This theory of vein formation is so well established that it is unnecessary 
to discuss it here. From facts which were developed in the detailed 
descriptions and which will later be assembled for further consideration, 
it is believed that the solutions were magmatic in origin. 

The theory of a magmatic origin for gold-quartz veins has been 
developed within the last 15 years by Vogt, Spurr, Kemp, and others. The 
formation of this class of veins is closely related to the formation of peg¬ 
matites—a question which has interested geologists for nearly a hundred 
years. It would be out of place in a report of this kind to enter into a 
detailed discussion of the voluminous literature bearing on the subject, 
but, for a proper understanding of the argument which follows, it is 
necessary to outline the theory of magmatic differentiation in so far as it 
applies to vein formation. 

The microscope has shown that in granites and similar rocks, the order 
of mineral crystallization is not that of relative fusibility; and synthetical 
experiments have proven that certain minerals always present in granites, 
can not be formed by dry fusion without the aid of water or other min¬ 
eralizers. These minerals are more abundant and better developed in 
pegmatites—rocks which accompany and in places pass by gradation into 
the large granite masses with which they are commonly associated. Not 
only has it been found that every intermediate gradation exists between 
granite and pegmatite, but that pegmatites, by decrease of feldspar, pass 
into quartz veins, apparently similar to those which are known to be 
deposited from circulating solutions. The microscopic study of granites 
in thin sections, together with chemical analyses, proves that the mineral 
constituents—especially quartz, the last to crystallize—contain inclusions 
of primary water which was imprisoned in the solidifying rock. It is be¬ 
lieved that the original magmas, from which granites are formed, contain 
water and other gases, and that as crystallization progresses these are 
gradually concentrated in a residuum. Pegmatites, and later quartz veins, 



GENETIC RELATION’S OF THE GOLD DEPOSITS. 


217 


are formed from this residual magma as it, through partial crystallization, 
becomes richer in water and relatively poorer in the minerals which are of 
early formation. In this process of differentiation it is impossible to draw 
sharp lines for, as Spun- states, “At one end of the series the true granites 
are not wholly igneous, and at the other end the quartz veins are not 
wholly aqueous. The processes which formed them all are nearer together 
than these terms signify.” 0 

The veins considered in the present report appear to be farther removed 
from the aqueous end of the series, and more closely allied to pegmatites 
than any gold-bearing veins which have previously been described. The 
first part of this chapter dealt with the mineral constituents of the ore- 
deposits, the succeeding sections will be devoted to the nature of the vein¬ 
forming solutions, their source, the conditions governing ore-deposition, 
and the origin of the spaces occupied by the veins. 

Nature of the Solutions. 

The best information as to the nature of the ore-forming solutions is 
furnished by a consideration of the primary minerals in the veins and the 
character of the changes that have taken place in the wall rock, but the 
absence of a sufficient number of analyses of the vein material and of the 
country rock, make anything other than a general discussion of the subject 
impossible. 

Microscopic examination of the vein quartz shows that it contains 
numerous gas- and liquid-filled cavities, and while analyses of these fluids 
are not available, their composition may be inferred from that of similar 
inclusions in granitic quartz which have frequently been analyzed. Such 
inclusions have been found to consist chiefly of water containing alkaline 
salts and carbon dioxide. Experiments have proved that silica, gold, and 
the sulphides of arsenic, antimony, iron, copper, lead, and zinc, are soluble 
in waters containing carbonates and sulphides of the alkalies, and their 
solubility is probably much greater under the conditions of high tempera¬ 
ture and pressure which obtained in the ore-depositing solutions. 

The solutions must have carried large amounts of silica, and the pro¬ 
duction of feldspars and mica indicates that aluminum, sodium, calcium, 
and potassium were present in about the order named. The sulphides of 
iron, copper, zinc, and lead are all primary minerals, and were therefore 
essential constituents of the ore-forming solutions. Gold was also present 

aSpurr, J. E., Ore Deposits of the Silver Peak Quadrangle, Nevada, Prof. Paper, 
U. S. Geol. Survey, No. 55, 1906, p. 131. 



218 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

and at least some of the solutions contained bismuth and tellurium. While 
carbonates were noted in only a few of the veins, carbon dioxide was 
probably a constant constituent. The mineral tourmaline, which is of rare 
occurrence in gold-bearing veins, contains boron, and some geologists 
have attributed to this element unusual properties as a mineralizing agent. 
Fluorine has been found necessary for the artificial production of mica, 
and Spurr has suggested that the alteration, near mineral veins, of ortho- 
clase to muscovite or sericite, is due to the presence of fluorine in the 
mineralizing waters.® The absence of orthoclase from the veins in which 
feldspars were identified, although a little potash mica is of common 
occurrence, indicates the possibility of some such action, but no fluorite, 
apatite, or other fluorine-bearing mineral was noted in any of the ore- 
deposits. 

The question of the degree of concentration which obtained in the ore- 
forming solutions is an interesting one, but until more experimental work 
has been done on the synthesis of vein minerals under varying conditions, 
it must, for the most part, remain unanswered. It is probable that under 
the unusually high pressures and temperatures, which are believed to have 
prevailed during ore-deposition, the concentration was relatively high— 
how high is not known. 

The presence of much soda-lime feldspar in some of the veins, and 
occasionally of the minerals, tourmaline and cyanite, point to unusual 
conditions in the formation of gold deposits. The character and asso¬ 
ciation of these minerals, together with the extensive alteration of the wall 
rocks, are indicative of a deep-seated origin under conditions of high 
temperature and great pressure. The metamorphism of the wall rock in 
many places is similar to that produced by igneous intrusions, and is ac¬ 
companied by the production of such typical contact minerals as garnet, 
hornblende, biotite, sericite, tremolite, and cyanite. In view of these facts 
it seems unquestionable that the temperature and pressure must have been 
much higher than those which usually prevail during the formation of 
gold veins. With the present knowledge of the subject any estimate of the 
probable temperature and pressure of vein-forming solutions must neces¬ 
sarily be rough, but an attempt may be of value and serve to bring out 
additional data bearing on the question. 

Wright and Larsen, as a result of their investigations, reached the con¬ 
clusion that vein and geode quartzes and coarse-grained siliceous pegma- 

oSpurr, J. E., Geology of the Tonopah Mining District, Nevada, Prof. Paper, 
U. S. Geol. Survey, No. 42, 1905, p. 231. 



GENETIC RELATIONS OF THE GOLD DEPOSITS. 


219 


tites were formed below 575° C., while graphic pegmatites, granites, and 
porphyries were in all probability crystallized above 575°. a If the same 
relation holds in regard to the gold veins described in this report, they 
must have been deposited at temperatures below 575° C., and from the 
metamorphic effects on the wall rocks and the character of some of the 
vein minerals, it is believed that the temperature of the vein-forming solu¬ 
tions was probably above the critical temperature of water, which is about 
365°. 

Becker, Graton, Lindgren, and others have recognized that the southern 
gold veins originally extended far above their present outcrops and it has 
been estimated that a depth of possibly 15,000 or 20,000 feet may have 
been removed by erosion. 1 ' Taking the average specific gravity as 2.7, the 
rock pressures at these depths would be, respectively, 17,550 and 23,400 
pounds per square inch. From facts which will be considered in detail in 
discussing the origin of the spaces occupied by the veins, the writer believes 
that the veins were formed in the zone of fracture and flowage as defined 
by Van Hise. There is evidence that, at the time of vein formation, hard 
quartzites were deformed chiefly by fracturing, while the softer rocks with 
which they are interbedded, adjusted themselves to unequal strain by 
flowing. The schists exposed at the Tellurium mine are the weakest rocks 
found enclosing veins, and their crushing strength is probably greater than 
that of good roofing slates, for they have undergone greater recrystalliza¬ 
tion. The crushing strength of strong slates averages from 15,000 to over 
30,000 pounds per square inch. ’While the figures given above are only 
roughly approximate they serve to indicate the great pressures which pre¬ 
vailed during the formation of the veins. For the rocks under considera¬ 
tion the higher figure is probably more nearly correct. 

Source of the Material. 

The composition of the gold-bearing veins is independent of the charac¬ 
ter of the wall rock, which varies greatly in different localities; and there¬ 
fore it is improbable that the vein material could have been derived from 
the enclosing formations. On the other hand, the composition and texture 
of some of the veins closely resemble that of pegmatites, and it is difficult, 
if not impossible, to account for the presence and association of such 
minerals as tourmaline, magnetite, ilmenite, and much soda-lime feldspar, 
on any hypothesis other than that of magmatic origin. 

oWright, F. E., and Larsen, E. S., Quartz as a Geologic Thermometer, Amer. 
Jour. Sci., 1907, vol. xxvii, pp. 446-47. 

bLindgren, W., Notes on the Dahlonega Mines, U. S. Geol. Survey, Bull. 293, 
1906, p. 124. 



220 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

Additional evidence in favor of this hypothesis is furnished by the 
alteration of the wall rock, an alteration which in places resembles on a 
small scale the contact metamorphism produced elsewhere in the area by 
the intrusion of granite into older sedimentaries. The great depth at 
which the veins were formed and the conditions of high temperature and 
pressure which must have prevailed, have already been discussed. It is 
obvious that the solutions from which the ore-bodies crystallized must have 
originated at points of even higher pressure and higher temperature; for 
in moving upward the pressure would decrease, and some heat be expended 
in raising the temperature of the surrounding rocks. These conditions 
would be fulfilled if we assume the presence of an underlying mass of 
igneous rock, and this conclusion was reached by an entirely independent 
line of reasoning (see pp. 102-103). 

An examination of the geological maps (Pis. I and II) shows that 
most of the gold-bearing veins are distributed in belts that roughly parallel 
the known contacts between intrusive granite and older sedimentaries. 
In the chapter on structure and metamorphism evidence was presented 
in support of the hypothesis that the veins are located chiefly along the 
limbs of anticlinal folds, and that the underlying granite extends highest 
in the crests of these folds. 

Another line of argument helping to prove a connection between the 
veins and granite is furnished by evidence bearing on their relative age- 
evidence which indicates that the formation of the veins marked the close 
of the period of granite intrusion and that they were not improbably 
contemporaneous in origin with the pegmatites and other residual 
differentiates. 

If the solutions that deposited the ore-bodies were derived by differ¬ 
entiation from the original granite magma, the granite itself would be 
expected to contain some gold, although the quantity might be so extremely 
small as to make its detection difficult and its quantitative determination 
impossible. Two samples of granite were tested in order to ascertain, if 
possible, the presence of any gold. One of these samples consisted of 
gneissic granite from the quarry at Columbia, and upon assaying it gave 
negative results. The other was obtained from an outcrop of weathered 
granite on the farm of II. Williams, one mile northeast of Rivanna Mills. 
After removing several inches of the partly decomposed rock in order to 
insure against possible contamination, an average sample was taken over 
an area of several square feet, and this was quartered down to give a final 
sample of about 5 pounds. A careful assay of this yielded 0.015 ounce 
of gold per ton, equivalent to about $0.31.° 


oThese two assays were made by E. E. Burlingame & Co., Denver, Colorado. 



GENETIC RELATIONS OF THE GOLD DEPOSITS. 


221 


In prospecting for gold, a 15-foot shaft was sunk on a pegmatite dike, 
located about 400 yards north of the granite outcrop described above. The 
pegmatite is partly fine-grained, but contains large angular masses of 
quartz showing a little pyrite (see sketch, p. 74). Mr. Williams states 
that some of this quartz assayed nearly $3.00 gold per ton. 

The results given above prove that the granite does carry gold in places, 
and while it would be rash to draw conclusions without taking a large 
number of samples, it is interesting to note that the granite in which gold 
was identified, is the porphyritic variety showing only slight schistosity, 
and that it is located near the crest of the hypothetical anticline (see pp. 
98-99), at a point where the granite is believed to have been formerly covered 
by schists at no great distance above the present surface. 

Deposition of the Ores. 

The manner in which ores are deposited and the causes which bring 
about precipitation are of the utmost importance in any consideration of 
their genesis, but exact knowledge on this subject is as yet very limited. 
In this district, the inaccessibility of most of the underground workings, 
which confined the detailed examination of ore-bodies to a very few 
localities, and the lack of a sufficient number of analyses, necessitates that 
the discussion of this subject be extremely limited. 

The precipitation of ores from solution may be brought about by any 
one of the following causes, or by two or more of them acting together: 

(1) Change in temperature. 

(2) Change in pressure. 

(3) Change in chemical composition due to 

(a) loss of some substance from the solution; 

(b) mixture with other solutions; 

(c) reaction between the wall rock and solution. 

It has been shown that the temperature and pressure of the ore-bearing 
solutions must have been higher at the points of origin than they were 
where deposition took place. Decrease in temperature was probably the 
chief cause in bringing about the separation of the gangue minerals, and 
possibly of the ore minerals as well. The effect of changes in pressure is 
not so well known, but certainly in the case of quartz, decrease in pressure 
is an important factor in causing supersaturation. The separation of some 
of the gangue minerals may have altered the composition of the solutions 
to such an extent that other minerals were thrown down. It is doubtful 


222 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

whether the solutions mingled to any extent with other solutions differing 
in chemical composition, for meteoric waters could hardly be abundant at 
a depth where the pressure was sufficient to prevent the formation of 
appreciable openings. 

Reaction between solutions and wall rock seems to have been an 
extremely variable factor in the deposition of the ores, and while these 
variations may in part be explained by differences in the character of the 
wall rock, many things indicate that there was probably considerable 
difference in the composition of the ore-forming solutions in different 
parts of the district. North of James River there is little evidence of 
important changes in the chemical composition of the wall rock. In places 
there has been considerable metamorphism, resulting in recrystallization 
and the formation of new minerals, but the changes in chemical composi¬ 
tion are comparatively slight, and are chiefly due to silicification. 
Sulphides have replaced some of the minerals in the wall rocks but usually 
to a very limited extent. 

In some of the ore-deposits south of the river, such as the London and 
Virginia vein, chemical interchange between the solutions and wall rock 
has been of the utmost importance. Porous rocks are of course most readily 
penetrated by solutions, and this may help to explain the occurrence of the 
replacement deposits in quartzites and quartz schists. In these deposits 
the chief replacement mineral is pyrite. The iron-bearing minerals in the 
country rock seem to have been attacked first, but in places practically all 
of the quartz has been replaced. Feldspars, if present, were altered to 
sericite, and this mineral is about the only gangue mineral left in some of 
the ores that are most concentrated. 

While nothing definite is known concerning the rate of ore deposition, 
the formation of the deposits was probably exceedingly slow and extended 
over a considerable period of time. This is indicated by facts connected 
with the probable manner in which the spaces occupied by the veins were 
formed—a question which is considered in detail in the following section. 

Origin of the Spaces Occupied by the Veins. 

Formerly it was generally believed that all true veins were deposited 
by aqueous solutions circulating through preexisting fissures. That some 
veins were formed in such openings is indicated by the presence of 
symmetrical banding, comb structure, and similar evidence, but in recent 
years doubts have arisen as to whether all veins could have been formed in 
this manner. The theory of replacement is applicable in many cases but 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 


223 


does not furnish a satisfactory explanation of the origin of veins which are 
accompanied by little or no replacement of the wall rock. 

As early as 1898, Russell, in describing certain “brecciated veins,” 
stated that the separation of the rock fragments “seems to be due in part, 
at least, to the crystallizing of the quartz and calcite.” He suggests “that 
these minerals, in crystallizing, have exerted a force analogous to the 
expansion of water on freezing, which has crowded the rock fragments 
asunder.”® 

The fact that growing crystals exert a linear pressure in the direction 
in which they grow, was noted by Jean Lavalle in 1853, b but no quantitative 
experiments seem to have been attempted until Becker and Day began 
their investigations. In 1905, Becker and Day, as a result of their experi¬ 
ments, stated: “It was at once evident that it [the linear force of growing 
crystals] amounted to many pounds per square inch, and as observations 
multiplied, it became reasonably certain that it is actually of the same 
order of magnitude as the ascertained resistance which the crystals offered 
to crushing stresses.” 0 In conclusion they called attention to the geological 
importance of the force of crystallization and pointed out the possibility 
of its action in widening quartz veins. 

Graton, in studying the gold-quartz veins in North and South Carolina, 
reached the conclusion “that the solutions, pushing their way along what 
may in many cases have been the merest fractures, actually forced the 
walls apart and made receptacles in which their load was deposited .” d 

Lindgren, advocating the explanation advanced by Graton as opposed 
to the hypothesis that veins could be formed through the force of crystal¬ 
lization, states that “it scarcely seems possible to attribute such power to 
it as would be necessary to force deep-seated crevices apart to form room 
for the crystals, and another strong objection is that it would seem im¬ 
possible that under these conditions comb structure and coarsely even¬ 
grained quartz could be produced.” 6 

The study of veins in the Virginia area, and especially of those 
exposed at the Tellurium mine, has convinced the writer that the force 

aRussell, I. C., A Preliminary Paper on the Geology of the Cascade Mountains 
in Northern Washington, 20th Ann. Rept. U. S. Geol. Survey, 1898-99, pt. ii, p. 207. 

&Compt. Rend., 1853, vol. xxxvi, p. 493. 

cBecker, G. F., and Day, A. L., The Linear Force of Growing Crystals, Proc. 
Washington Academy of Sciences, 1905. vol. vii, pp. 286-287. 

dGraton, L. C., Reconnaissance of Some Gold and Tin Deposits of the Southern 
Appalachians, U. S. Geol. Survey, Bull. 293, 1906, p. 60. 

eLindgren, W., The Relation of Ore-Deposition to Physical Conditions, Economic 
Geology, 1907, vol. ii, p. 107. 



224 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

exerted by growing crystals must have been the chief factor in the forma¬ 
tion and enlargement of these gold-bearing veins. A discussion of the 
facts on which this conclusion is based, is given below. 

The “Middle” vein at the Tellurium mine consists of a series of lenses, 
varying in size, but remarkably symmetrical in form (see figs. 13-15). 
Horizontal sections through these lenses resemble the vertical sections in 
every way. The wall rock is a fine-grained, highly foliated schist contain¬ 
ing scattered crystals of garnet, and closely approaches a slate in perfection 
of cleavage and fineness of texture. The schistosity is parallel to the 
bedding and older than the formation of the vein, which is conformable in 
strike and dip. Thirty feet northwest of the “Middle” vein the schist is 
interbedded with a layer of quartzite about 6 feet thick, known as the 
“Big Sandstone” vein. This quartzite is also slightly schistose parallel to 
the bedding. It encloses veinlets similar in composition and texture to 
the “Middle” vein and evidently formed at the same time and in the same 
manner, but these veinlets frequently cut across the schistosity of the 
enclosing rock (see fig. 12). A detailed description of these veinlets and 
of the “Middle” vein, together with a petrographic description of the wall 
rocks, is given on pages 157 to 170. 

The fact that the veins of this district show practically no crushing or 
other evidence of deformation, although the surrounding country rock is 
intensely foliated, is sufficient proof of their formation since the crustal 
movements that produced the schistosity, and moreover in some of the 
harder rocks they occasionally cut directly across the prevailing schistosity. 

The space occupied by lenticular veins is sometimes accounted for on 
the supposition that displacement has occurred along an irregular fault, 
but in the case of veins like the “Middle” vein, this explanation would be 
improbable, in view of the symmetrical shape of the lenses, which is the 
rule even where adjoining lenses differ greatly in size. This argument is 
confirmed by the fact that the folia of the enclosing schist, where in contact 
with the vein, conform absolutely to the curvature of the lenses. It may 
also be mentioned that single detached lenses are occasionally present near 
some of the veins (see PI. X, fig. 2) and such occurrences can not be 
explained by any method of faulting. In passing away from the lenses 
the flexures in the schist gradually straighten, so that at a distance of 
about 2 feet the cleavage is straight and uniform. 

From the facts stated above, it is concluded that the “Middle” vein 
could not have been formed in a preexisting fissure, and since the contacts 
with the wall rock are sharp and without evidence of replacement, the 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 225 

lenticular spaces must be due to pressure. That the rock pressure during 
vein-formation was greater than the crushing strength of the schist, is 
proved by the uniform curves of the folia—the schists have made room for 
the lenses by flowing and not by fracturing. The faint line connecting the 
lenses shows that the ore-bearing solutions, following the lines of least 
resistance, entered along the planes of bedding and cleavage; but great 
pressure was necessary to expand such microscopic openings into lenses 
2 or 3 feet in thickness. How could such a pressure be developed? 

There are two hypotheses that may be advanced to account for the 
existence of such pressure: (1) The ore-bearing solutions were forced in 
from below under sufficient pressure to push the walls apart, and (2) the 
pressure was exerted by the crystallization and growth of the vein-forming 
minerals. 

The chief argument against the first hypothesis is the symmetrical and, 
in places, almost spherical shape of the lenses. If the expansion of the 
openings was due to fluid pressure exerted by the ore-bearing solutions, the 
pressure would necessarily have been equal at all points of contact between 
the fluid and the walls, except for the slight variations due to friction and 
difference in elevation. The enclosing schists are apparently uniform in 
texture and composition, and therefore would offer uniform resistance to 
the fluid pressure at all points, except those lying in the plane of cleavage 
along which the solutions entered. Under these conditions very flat 
lenticular- or tabular-shaped openings must have been formed. In ex¬ 
plaining, by means of this hypothesis, the formation of a series of openings 
similar to the lenses shown in figs. 13 and 15, it would be necessary to 
assume the presence of areas of unusual weakness at every point where an 
enlargement of the vein occurred. Moreover, since most of these enlarge¬ 
ments are symmetrical, it would be necessary to assume that, at these 
points, there were similar areas of weakness on both sides of the cleavage 
plane. Such assumptions are almost inconceivable. 

Unless the spaces were filled by ore-deposition as soon as formed, the 
fluid pressure would have to be uniformly maintained in order to prevent 
the walls from collapsing. The great fluidity of the solutions is indicated 
by the microscopic size of some of the openings along which they entered. 
Additional evidence against the formation of the openings by fluid pressure 
is furnished by the existence of large lenses, consisting of a number of 
smaller quartz lenses separated by feldspar and layers of schist. (See 
fig. 14.) 

In a previous paragraph it was mentioned that the veinlets occur ring- 
in the bed of quartzite frequently cut across the schistosity. This is ex- 


226 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

plained by the greater rigidity and more nearly massive texture of the 
quartzite which caused it to rupture under the forces of deformation while 
the weaker schist yielded by flowing. In other words, the rigidity of the 
quartzite under the conditions of vein-formation was probably greater than 
the rock pressure, while that of the schist was less. The line of least 
resistance for the ore-bearing solutions which entered the quartzite was 
frequently along minute fractures instead of along the poorly developed 
cleavage planes, and therefore the veinlets do not always conform to the 
structure of the enclosing rock. If the spaces occupied by the veins are 
due to fluid pressure, it is difficult to understand why veins a foot or more 
in width were formed in the quartzite, when the less rigid schist was present 
on either side. Under these conditions veins might be expected along the 
contact between the quartzite and schist, or wholly within the schist, but 
not in the quartzite. 

In view of all of the facts outlined above, it seems very improbable, if 
not impossible, that the vein spaces could have been produced by fluid 
pressure and then filled by ore-deposition. 

According to the second hypothesis, the solutions entered along narrow 
openings—probably capillary or subcapillary in size—and while under 
pressure, the pressure was insufficient to expand the openings. Crystalliza¬ 
tion began at favorable points, possibly about grains of quartz, and as the 
crystals grew, the walls were locally pushed aside. At first a growing lens 
may have consisted of a single crystal, but as the folia began to separate, 
others would form in the space created immediately around the original 
crystal, where the pressure was lowered by its supporting effect. Since the 
resisting pressure was equal on opposite sides of the cleavage plane the 
growth would be symmetrical with reference to that plane. When once 
started a lens would continue to grow as long as the material for growth 
was available. 

There are many points of similarity between the formation of these 
lenses and the growth of chert concretions in limestones, or of garnets and 
similar pseudophenocrysts in fine-grained schists. The localization of 
growth is probably due to the physico-chemical law by which solutions 
become supersaturated with respect to large crystals, while at the same 
time they may exert a solvent action on small crystals of the same 
substance. 

When individual crystals are enlarged their shape is controlled by the 
tendency to form crystal faces, by the external forces resisting growth, and 
by the accessibility of the material from which they are composed. When 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 


227 


masses, consisting of numerous crystals, are enlarged by crystal growth, 
the resulting shape is controlled chiefly by the forces resisting expansion. 
The schist enclosing the lenses described above has a much greater tensile 
strength parallel to the schistositv than across it, and the folia offer con¬ 
siderable resistance to rupture, even when the rock is under sufficient 
pressure to make it more or less plastic. The resistance offered by these 
folia to the enlargement of the ore-bodies is somewhat analogous to surface 
tension, which in liquids causes the assumption of shapes giving a maxi- 



Fig. 21.—Sketch showing recrystallization of quartz about garnets which are of 
later origin than the foliation of the schist. Thin section cut at right angle to 
cleavage. With analyzer. Q, quartz; M, mica; G, garnet. Enlarged about 
20 diameters. 

mum volume for a minimum exposure of surface. The solubility of quartz 
decreases with decrease in pressure and supersaturation is reached first 
where the pressure is lowest. If the resistance to growth were equal in 
all directions spherical bodies would be formed instead of lenses, and under 
any given condition the shape produced is that shape which requires the 
least expenditure of energy. 





228 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER EASIN'. 


The fact that difference in pressure may be an important factor in 
determining the location of crystal growth, is strikingly illustrated by the 
recrystallization of quartz around the garnets occurring as pseudopheno- 
crysts in the knotted schists of the area. These schists form the wall rock 
of the “Middle” vein, and it should be noted that where this variety of 
garnet schist has been found elsewhere in the area, it occurs only in the 
immediate vicinity of granite contacts. The garnets are of later origin 



Fig. 22.—Sketch showing radial arrangement of quartz in garnetiferous schist. Thin 
section cut parallel to cleavage. With analyzer. Q, quartz; .1/, mica; G, garnet. 
Enlarged about 15 diameters. 

than the schistosity of the rock, and it is believed that their formation in 
the schist at the Tellurium mine, is due to the close proximity of granite 
rather than the metamorphic action of the vein-forming solutions. In 
either case their origin must have been practically contemporaneous with 
the formation of the veins. Under the microscope the schists are seen 
to consist essentially of elongated quartz grains and small flakes of mica, 
the two minerals being interleaved to form thin layers or imperfect alter¬ 
nating bands. The garnets in their growth have pushed the folia aside, 





GENETIC RELATIONS OF THE GOLD DEPOSITS. Jd29 

and opposite the points of greatest pressure the mica bands run closer 
together, while the quartz removed from these points has recrystallized 
between the folia and close to the garnets where the pressure was least. 
(See fig. 21.) The transfer of the material was undoubtedly due to the 
small amount of water present in the rock; solution occurred where the 
pressure was greatest and deposition where it was least. In recrystallizing 
the quartz grains were roughly oriented so that their greater elongation 
points toward and away from the garnets. (See fig. 22.) 

The partial concentration of feldspar near the ends of quartz lenses, 
and in small separate lenses practically free from quartz, is caused by the 
selective power which enables a growing crystal to abstract from solutions 
material like itself ; and this may be taken as additional evidence in favor 
of the second hypothesis. 

An examination of the lenticular veins show that in some instances 
neighboring lenses in expanding have grown into one another so as to form 
double lenses, and it is not unlikely that other occurrences of this sort have 
disappeared through continued growth. The large lenses composed of 
smaller ones, such as the occurrence shown in fig. 14, were probably caused 
by the circulation of the ore-forming solutions along several adjoining 
cleavage planes at the same time, thus permitting the simultaneous growth 
of lenses at a number of points close together. An alternative hypothesis 
is that the solutions were deflected into new channels after a lens had been 
formed causing subsequent deposition to take place about other nuclei 
located between adjacent folia. 

In describing the veinlets occurring in the quartzite, reference was 
made to the absence of the symmetrical lenses which are characteristic of 
the vein in the schist. This difference in the shape of the ore-bodies is 
probably chiefly due to the difference in texture and rigidity of the two 
varieties of wall rock. If crystallization began at separate points along 
the fractures in the quartzite and exerted a force tending to open spaces, 
the rigidity of the rock was sufficient to cause the walls to separate for an 
appreciable distance beyond the points where the pressure was applied. 
Any openings formed in this way were filled by deposition from the solu¬ 
tions, and therefore the tendency was to form veins without important 
variations in width. In other words, rigidity of the wall rock under the 
conditions of ore-deposition is an essential factor in the formation of veins 
having a! uniform width. This is another illustration of the law controlling 
the growth of bodies by crystallization, in opposition to outside forces. 

The composition of the quartzite has probably aided in producing uni¬ 
formity in the growth of the veins which it encloses, and this may have 


230 GEOLOGY OF THE GOLD BELT IN THE JAMES EIVER BASIN. 

been of as much importance as the rigidity. Since the quartzite is com¬ 
posed almost entirely of quartz grains, the walls of the fractures would 
furnish innumerable nuclei on which the vein quartz could separate out. 
In thin sections showing the contact between the quartzite and vein quartz, 
when examined under the microscope, it may be seen that the quartzite 
grains along the contact have been enlarged, and that there is therefore 
a gradation instead of a sharp division in passing from one to the other. 

Under the conditions which prevailed during the vein-formation, the 
gneiss, which forms the wall rock at the Young American mine, appears 
to have been intermediate in rigidity between the quartzite and knotted 
schist described above. It was folded and contorted by movements pre¬ 
ceding the deposition of the ores, and adjustment took place partly by 
flowing and partly by minor faulting along fractures and shear zones. The 
vein-forming solutions entered along these lines of weakness and the en¬ 
largement of the openings was brought about by the same causes that 
operated at the Tellurium. In the gneiss, most of the small quartz masses 
and some of the larger ones are lenticular in form, but these lenses are 
flatter and as a rule less symmetrical than those of the “Middle” vein at 
the Tellurium. They are most plentiful in some of the shear zones. (See 
fig. 9, p. 130, and PI. X, fig. 2.) 

The hypothesis that vein spaces may be enlarged through the force 
exerted by growing crystals, furnishes a logical explanation for the 
presence of numerous detached fragments of the country rock in the veins 
of some districts. These occurrences have usually been explained on the 
supposition that the veins were deposited in preexisting fissures, and that 
the inclusions represent fragments which have fallen from the walls. That 
this is sometimes true can not be questioned, though it seems probable that 
such cases are relatively rare. Where the country rock has been shattered 
so that numerous small fractures are formed, ore-deposition may take place 
in any number of them at the same time, and as the veinlets grow the 
individual fragments of country rock are gradually separated. According 
to this hypothesis of vein-formation there is no essential difference between 
the cementation of many breccias and the formation of branching or reticu¬ 
lated veins. The processes by which both are formed are exactly the same 
and differ only in degree. 

At the Morrow mine, in Buckingham County, ore-deposition seems to 
have occurred in a zone of fracturing; in places the ore-body consists of 
vein matter with minor inclusions from the walls, while elsewhere the ore 
occurs in reticulated veinlets which ramify in all directions through the 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 


231 


barren schists that form the country rock. All gradations exist between 
these two extremes. (See fig. 20, p. 204.) The detached masses of 
country rock have apparently reached their present positions without 
noticeable rotation, for as a rule the schistosity of the inclusions is parallel 
to that of the neighboring walls. 

The localization of the veins of this district in or near the more rigid 
rocks, especially quartzites, is very noticeable, and may indicate that at 
greater depth where the pressure was necessarily greater the solutions were 
unable to force their way through the fine-grained and more plastic rocks. 
The greater porosity of the quartzites may also have been a factor. 

General Conclusions as to the Origin of the Gold Deposits. 

The primary gold deposits of this area, while varying somewhat in gen¬ 
eral character, are all intimately related, and owe their origin to the same 
cause, namely, the intrusion of granitic rocks into the older sedimentaries. 
They are of two types—quartz veins and replacement deposits—with inter¬ 
mediate gradations between the two extremes. The ores were deposited 
from highly siliceous and alkaline solutions which ascended from below 
under great pressure and high temperature. The solutions were magmatic 
in origin and residual from the crystallization of the underlying granite. 
This conclusion is borne out by the grouping of the ore-deposits around 
granite contacts; by the presence and association in the veins of soda-lime 
feldspar, tourmaline, magnetite, and ilmenite; by the metamorphism of 
the wall rocks with the production of such typical contact minerals as 
garnet, hornblende, biotite, sericite, tremolite, and cyanite; by the presence 
of gold in the granite and its associated pegmatites; and by the evidence 
as to the relative age of the granites, pegmatites, and veins. It is believed 
that the precipitation of the ores was due chiefly to decrease in temperature 
and pressure, though in the replacement deposits interchange of material 
between the solutions and country rock was an important and perhaps 
the principal factor. 

The ores were deposited at great depths below the surface where the 
pressure of the overlying rock was sufficient to prevent the formation of 
open spaces appreciable in size. The solutions forced their way upward 
along cleavage planes and, in the more rigid rocks, along minute fractures. 
When deposition began these spaces were gradually expanded by the force 
of crystallization. The formation of the replacement deposits was probably 
due to differences in the ore-bearing solutions, but the character of the 
country rock may have had a determining influence. 


232 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

The veins in this district differ markedly from the typical auriferous 
quartz veins of California, which many geologists regard as having been 
formed by magmatic waters derived from cooling granites. The California 
veins are much later in origin, have been subjected to less erosion, and 
therefore their present outcrops were much nearer the surface when ore- 
deposition took place. This suggests that many of the distinguishing char¬ 
acteristics of the two types are due to the depth below the surface at which 
the veins were formed. It is not improbable that at greater depth the 
California veins more closely resemble the gold deposits described in the 
present report, and that the upper portions of the Virginia veins, long 
since removed by erosion, were in many respects similar to the veins which 
are now being worked for gold in California. 

SECONDARY ENRICHMENT. 

The distribution of the gold in the ore-deposits is a question of great 
economic importance, and it is regretted that so little is known concerning 
the subject. The lack of sufficient development work at any of the mines, 
which were accessible when the area was studied by the writer, makes it 
impossible to reach definite conclusions in regard to secondary enrichment, 
and therefore the following discussion is necessarily brief. 

The facts gathered indicate that the gold is very irregularly distributed 
through the veins. There appear to be more or less well-defined pockets 
or ore shoots of relatively rich ore, but the size and distribution of these 
is unknown. It is probable that the values vary from point to point in 
depth as well as along the strike of the veins, and this increases the difficulty 
of ascertaining the extent to which secondary enrichment has been a factor 
in determining the present value and distribution of the ores. 

It seems unquestionable that the veins were much richer near their 
outcrops than they are at even a short distance below the surface. The 
greater production of the mines when they were first worked can not be 
attributed solely to the fact that the ores were oxidized, and therefore free- 
milling, for the reports of such reliable observers as Silliman, Ansted, and 
Henwood, furnish evidence of the unusual richness of the veins when the 
mines were first opened. Henwood, in describing the Morrow mine, ex¬ 
pressed his belief that the gold values decreased in depth (see p. 205), and 
cited the statistics of production in support of this contention. Ansted, in 
his report on the same property, mentions that near the surface the gold 
is indifferently disseminated through the quartz, rotten schists, and enclos¬ 
ing walls, while deeper down it gradually collects together and is found 


GENETIC RELATIONS OF THE GOLD DEPOSITS. 


233 


chiefly within the quartz bands. This local enrichment of the vein and 
wall rock near the surface, is probably due chiefly to the mechanical con¬ 
centration of some of the gold formerly contained in the now eroded por¬ 
tions of the ore-bodies, though it is not unlikely that chemical processes 
have aided in the concentration. Gold is one of the most insoluble sub¬ 
stances found in nature, but the long period during which erosion has been 
almost at a standstill has given every opportunity for concentration to take 
place through solution and redeposition. Most of the gold that may have 
been dissolved in this manner was probably reprecipitated before it had 
been carried far, for precipitating agents were plentiful. 

In some of the deeper openings which extended below the oxidized 
zone, secondary pyrite is found occurring along joint planes and fractures, 
but the development work is insufficient to determine whether or not there 
has been any enrichment of the gold values at this depth. 

AGE OF THE OEE-DEPOSITS. 

Geologists have usually assumed that all the primary gold deposits in 
the Southern Appalachian region belong to the same metallogenetic epoch. 
While it is not improbable that this is true, it has not, as yet, been estab¬ 
lished by sufficient detailed geological work. Many of the older geologists 
considered the veins contemporaneous with the enclosing rocks which were 
classified as “primary.” Becker and most of the recent workers have placed 
the deposits in the pre-Cambrian. 

The veins in the district covered by the present report, were formed 
after the intrusion of the granite, and probably represent the final stage 
in the period of igneous activity which preceded their deposition. They 
show no evidence of having been subjected to the great crustal movements 
which so intensely metamorphosed the enclosing sedimentary rocks and 
even the massive granites. These movements were probably inaugurated 
and the sedimentaries rendered schistose prior to the intrusion of the 
granites with which they are in contact. The well-developed schistosity of 
most of the granitic rocks is evidence that the movements continued 
throughout the greater part of the period covered by their intrusion. The 
porphyritic facies of the granite show decreasing pressure effects and many 
of the pegmatites are practically massive. These facts are discussed at 
greater length in the chapter on structure and metamorphism. 

The profound changes to which the ore-bearing formations were sub¬ 
jected prior to the intrusion of the granite, indicate that a considerable 
time interval must have intervened between the deposition of the sedi- 


234 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

ments and the formation of the veins; and this together with the lack of 
important crushing, or other evidence of disturbance in the quartz veins, 
suggests that they are later than pre-Cambrian in age. 

Subsequent to the intrusion of the granite and the formation of the 
gold veins, sufficient time elapsed for erosion to remove the overlying 
material and expose the deep-seated granite, before the surface was again 
depressed to receive the sediments of late Ordovician time. The Arvonia 
slates, which are known to be Cincinnatian in age, were laid down on the 
older schists and in places on granite which is only slightly schistose. 
Therefore even the granites which were last to solidify are older than 
Cincinnatian in age. The slight evidence of dynamic metamorphism ex¬ 
hibited by the gold-bearing veins was probably induced by the movements 
which elevated and folded the Ordovician sediments. 

A consideration of the facts outlined above makes it appear reasonably 
certain that the primary gold deposits in the James River basin are older 
than Cincinnatian in age, and they are probably younger than pre- 
Cambrian. Until further evidence is available, the writer is of the opinion 
that the veins should be classified as Cambrian. 


CHAPTER VII. 


PLACERS. 

Gold has been found in the gravels of all streams that cross the gold- 
bearing rocks of this area, and also in certain ancient stream gravels that 
are now located high above the neighboring water-courses. Most of these 
“branch” gravels, as they are locally called, have been worked, and some 
of them reworked a second time in order to recover the precious metal which 
they contained. Gold also occurs, concentrated in considerable quantity, 
in the accumulations of residual decay overlying the gold-bearing veins 
and in their immediate vicinity, and such deposits have been profitably 
worked in a number of places. 

When the gold-bearing veins and the enclosing country rocks were 
exposed by denudation to the chemical and mechanical action of the agents 
of erosion, the slow process of concentrating the heavier and more resistant 
constituents into the placer deposits began, and this has been in continuous 
operation ever since. The minerals with least resistance are attacked first, 
their decomposition making easier the disintegration of the remainder, 
and under this process the rocks slowly go to pieces. If the products of 
weathering collect faster than the streams can transport them, deep 
residual soils are gradually formed. Of the common minerals, quartz is 
the hardest, the least soluble, and does not undergo chemical decomposi¬ 
tion ; and since it is the principal vein-forming mineral, the veins usually 
extend for some distance above hard rock into the overlying mantle of 
residual decay, but frost and plant roots step by step break up even the 
larger veins and add their constituents to the soil. 

With the breaking down of the rocks and the formation of disintegrated 
material, the next step in the process of concentration is that of sorting 
and transportation. Expansion and contraction, due to changes in 
temperature and to freezing and thawing where water is present, cause 
the soils to gradually creep down hill. The wash of rain water aids in 
this slow movement by carrying off the lighter particles, while the heavier 
fragments lag behind. In this way a partial concentration of the heavier 
constituents in the residual decay is brought about, and as gold has a very 
high density and is relatively insoluble, it frequently occurs in considerable 
quantity in the decomposed material lying vertically above gold-bearing 
veins, and along the hill slopes immediately below them. The gold found 


236 GEOLOGY OF THE GOLD BELT IN' THE JAMES RJVER BASIN. 

in such localities has not traveled far and is therefore comparatively rough 
and angular, while the quartz and other rock fragments which may accom¬ 
pany it do not show the rounded waterworn surfaces of stream gravel. 
Deposits of this nature have been worked in a number of places, notably 
at the Tellurium and Waller mines where they are said to have been 
very rich. 

The slow creep of the soil and occasional heavy rains gradually bring 
the products of disintegration within reach of running streams, which 
continue the work of concentration, but here an additional process is 
brought into play—that of abrasion. The swiftly flowing streams rapidly 
remove the finer sediments in suspension while the heavier fragments are 
rolled along more slowly by the current, constantly striking and grinding 
against one another. This continual impact and friction, in time, is 
sufficient to wear away the toughest rocks, and quartz while hard is rather 
brittle. The gold, being malleable, escapes most of this comminution, and 
because of its high specific gravity settles through the sand and gravel 
until it finds lodgment close to bedrock. In this manner the placer 
deposits are gradually formed in the stream beds. 

If for any cause the course of a stream is changed, the placer gravels 
which have been formed in its bed may remain as deposits of dry gravel 
which, as the stream deepens its channel, are left high above the water 
level. Placer gravels of this type were at one time extensively worked 
on the Collins place, a mile northeast of Lantana. 

As a result of the hammering which they have undergone, the gold 
nuggets found in placer deposits are smooth and rounded, differing in this 
respect from those found closer to the original vein deposits. The placer 
gold is, moreover, somewhat purer or of a higher degree of fineness than 
the vein gold, for during the long time in which it has been subjected to 
the oxidizing and solvent action of the agents of weathering, impurities 
have been largely removed. In other words, the gold has passed through a 
sort of natural refining process as well as one of concentration. 

The unusual richness of the branch gravels as compared with the 
original vein deposits from which they were derived is due to the great 
length of time in which the process of concentration has been going on, 
the large amount of material which has been worked over, and the very 
limited extent of the gold-bearing gravels formed. 

The area has probably been subjected to erosion almost continuously 
since the close of Ordovician times, and this has affected the gold deposits 
ever since the veins were first exposed by degradation. Everything bearing. 


PLACERS. 


V61 


on the genesis of the gold veins, as has been stated in detail elsewhere, 
indicates that the portions of the veins that are now exposed, were formed 
at a great depth below the surface; and a study of the physiography of the 
area gives independent evidence as to the thousands of feet of overlying 
rock removed by erosion. The veins, when formed, must have extended 
several thousand feet above the present surface, and while most of the gold 
originally contained in this vast amount of material was probably carried 
away and lost, a considerable proportion of the metal, because of its tough¬ 
ness, resistance to ordinary solvents, and high specific gravity, has been 
retained and concentrated into the relatively small bulk of material com- 
posing the placer gravel deposits. 

The placer gravels of Virginia are limited to the immediate vicinity 
of the vein-deposits from which they have been derived, and nowhere do 
they cover large areas, being almost entirely confined to the branches and 
smaller creeks. Much of the placer gold is coarse, and this together with 
its comparative roughness indicates that it has not traveled far. The 
branches are frequently reported to have been richest near the veins, and 
none of them was worked for any great distance below the lowest known 
veins, usually less than a mile. They carried little or no value above the 
veins, and in fact many of the veins, which seldom outcrop, were located 
by panning up the branches. Large deposits of low-grade gravels, such 
as those in California which were extensively worked at one time by 
hydraulic methods and are now being worked by dredging, have not been 
found in Virginia. The only place within the present area where it would 
be possible to find similar gravels is in the Triassic beds, which are exposed 
near the southern boundary of the area. It is interesting to note that 
Becker, working in a similar district, found transported gold in the 
Newark (Triassic) conglomerates of North Carolina.® 

During the time in which the present branch gravels were being con¬ 
centrated, the physiographic conditions in Virginia were not suitable for 
the formation of low-grade placers. The fact that approximate pene- 
plaination has continued for a long period of time is probably the reason 
that large deposits of auriferous gravels are absent and that the placer 
gravels are all concentrated close to the primary deposits. The factors 
which make the Virginia branches such perfect “concentrators” having 
been outlined above, it might be of interest, for purposes of comparison, 
to state briefly the conditions under which the large low-grade deposits of 
California were formed. 

oBecker, Geo. F., Reconnaissance of the Gold Fields of the Southern Appa¬ 
lachians, 16th Ann. Rept., U. S. Geol. Survey, 1894, pt. iii, pp. 315-316. 



238 GEOLOGY OF THE GOLD BELT IX THE JAMES RIVER BASIX. 

In California the mountain streams crossing the gold area are swift, 
and consequently their powers of transportation high; the rainfall is light, 
but largely confined to certain seasons of the year when sudden floods are 
not uncommon. The result of these conditions is to give a maximum of 
transportation efficiency for a given volume of water, and the streams 
are able to carry down vast quantities of gravel and even boulders of con¬ 
siderable size. When the streams, however, reach lower elevations and 
enter the large valleys that stretch back from the coast, their velocity is 
checked and their power of transportation suddenly diminished, causing 
them to drop a large part of their load. In this way gravel deposits, which 
often cover large areas to a depth of 30 or even 100 feet or more, and 
which in places contain small quantities of irregularly distributed gold, 
have been built up in some of the valleys. 

The placer gravels were extensively worked during the early days of 
mining in the James River district, and in many places they are reported 
to have been very rich. At this late date no authentic records are obtain¬ 
able that would give the amount of gold produced by the placer deposits 
of this district, or even of the State as a whole, but it is unquestionable 
that a very large percentage of the total gold production in Virginia has 
been derived from the gold-bearing gravels. While most of these branch 
gravels were worked out years ago, it is still possible to estimate the extent 
of the deposits from the irregular piles of gravel that were always left 
behind. 

In this section all known placer deposits that could be profitably worked 
by the simple methods formerly employed, were long ago exhausted, and 
it is improbable that new ones will be discovered in the future. In regions, 
such as this, which have long been inhabited, one can no longer expect to 
find rich, easily workable placer gravels, and this is especially true in a 
section where the presence of gold has been known for so many years, and 
where so much prospecting has been carried on. The presence of gold in 
such deposits is so easily detected, even by those with little experience, 
that there is little likelihood of its being overlooked, and the methods that 
may be used to recover it are so simple and inexpensive that the deposits 
are quickly worked out. 

Much gold was lost by the wasteful methods commonly employed when 
the branch gravels were first worked, and it would probably pay to rework 
many of these deposits, if a suitable method could be devised for handling 
them cheaply on a large scale. In the early days of mining the branches 
were usually leased, and the gravel washed in rockers by tributers who 


PLACERS. 


239 


payed a certain percentage of the gross proceeds, as a rule a fifth of the 
gold recovered. Some gold escaped recovery or was overlooked, and when 
the gravels were poor or mixed with sufficient clay to make washing difficult 
they were left untouched. Panning shows considerable gold even in the 
gravels that have been washed, and these also contain some mercury and 
amalgam lost by the early miners. Most of this gold is fine but it is 
granular and easy to recover; the gravel is small in size, contains but little 
sand and there are no boulders. In most places the grade is not sufficient 
for sluices. 

The only known placer gravels which have not been worked are those 
that occupy the bed of Byrd Creek and in places underlie the adjacent low¬ 
lands, but up to this time the difficulties involved in the profitable handling 
of these gravels have proved insurmountable. While they have not been 
systematically prospected, it seems certain that the Byrd Creek placer 
gravels must contain much gold. Byrd Creek is one of the larger streams 
of the area, and it cuts directly across the gold belt, while its tributaries 
include most of the rich branches formerly worked for gold. 

So far as known the only effort to work the Byrd Creek gravels was 
made about the year 1900. During the summer, while the water was low, 
an attempt was made just above Bowles’ Bridge, 4 miles northeast of 
Columbia, to turn the creek aside, sink pits down to bedrock in the stream 
bed, and wash the gravel in rockers, but this experiment proved unsuccess¬ 
ful, for the water could not be kept out and the pits soon caved. It is said 
that the gravel was about 7 feet deep and that there was no overburden of 
mud; bedrock looked like slate and was covered with a layer of soft, decom¬ 
posed rock that made shoveling easy. The gold was coarse, most of it being 
“about the size of wheat grains.” The conditions may have been unusually 
favorable at this place as a branch that had rich placer gravels entered the 
creek not far above. 

The only other information bearing on the value of the Byrd Creek 
gravels is furnished by some prospecting done on the Bertha and Edith 
tract, which lies on the east side of the creek 3 miles northeast of Columbia. 
All the branch gravels on this place were washed for gold years ago, and 
the placers along Great Camp and Maple branches are reported to have 
been very rich. At that time Big Byrd Creek was dammed to furnish 
power for a mill located near the southern end of the property, and the 
mill pond thus formed covered about 3 acres including the lower portions 
of Great Camp and Little Camp branches. The gravels covered by the 
old mill pond, which has since been drained, have never been worked. In 


240 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

1897, a company, which held the property under lease and option, sank a 
number of prospect pits in the flat near the mouth of Great Camp Branch 
and started to work the deposits, but all work was discontinued when their 
nearly completed mill and cyanide plant were destroyed by fire. Where 
the prospect pits were sunk the gravel was found to be from 1 to 2 1 4 feet 
thick and covered with an overburden of from 4 to 7 feet of sandy soil. 
It is stated that all the gravel carried gold, the values averaging from 
1 to 2 pennyweight per square foot. The amount of gold did not seem 
to vary with the thickness of the gravel and most of it was found close to 
bedrock. The gold was quite coarse, many of the grains weighing from 
0.10 to 0.20 pennyweight, while the largest nugget recovered weighed 1.78 
pennyweight. 

These facts prove that coarse gold was carried by the branches as far 
as the creek, and it can hardly be doubted that the gravels of the creek 
bed contain sufficient gold to make their mining profitable, providing a 
suitable method of handling them can be devised. 

Any successful method of working these placer gravels will have to take 
into consideration the following facts: 

(1) Along much of its course Byrd Creek is bordered by steep banks, 
which in places give way to high bluffs, and this would make its diversion 
difficult if not impracticable. 

(2) The mean discharge of the stream is large and it is subject to 
occasional floods. 

(3) There is not sufficient fall in the creek to allow the emplovment 
of sluices, and the disposal of tailings would be difficult. 

(4) While no boulders occur in these gravels, the banks are in many 
places lined with trees, and their roots would probably interfere with 
dredging or similar methods of mining. 

(5) At several points there are rapids in the creek caused by ledges 
of resistant rock which outcrop in the bed of the stream. 


CHAPTER VIII. 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 

TYPES OF COPPER DEPOSITS. 

Copper ores have been prospected at three localities in this district and 
the ore-deposits consist of two distinct types. The Lightfoot mine on the 
southeast side of Slate River about 2 miles northwest of Arvonia, and the 
Anaconda mine, located 3y 2 miles west of Johnson and 5 miles north of 
Dillwyn, belong to one type, while the mines near New Canton are opened 
in a very different kind of ore-deposit. 

Ores of the type first mentioned occur as veins or lenticular masses in 
greenstone schists derived from basic igneous rocks, while ores of the last- 
named type are found impregnating crystalline schists, adjacent to their 
contact with an intrusive granite (quartz-monzonite with a dioritic border 
facies). In both types the principal ore-minerals are pyrite, more or less 
auriferous, and chalcopyrite. The origin of the ores belonging to each 
type will be discussed after the individual occurrences have been described. 

DESCRIPTION OF INDIVIDUAL MINES. 

The Lightfoot Mine. 

Location .—The Lightfoot copper mine is located on the southeast side 
of Slate River, 2 miles northwest of Arvonia. 

History .—The property was first worked for gold (see p. 207), but the 
•copper deposit was opened shortly before the war by a company which is 
said to have shipped 100 tons of the ore to a smelting house in Baltimore, 
where it brought $80 per ton.® The outbreak of the war in 1861 put a 
stop to work at the mine, and since that time while there have been some 
spasmodic attempts to develop the property (the last about 190-4) little 
has come of them. A shaft has been sunk to a depth of 85 feet, the collar 
of the shaft being about 20 feet above the level of the nearby stream, and 
•several short drives have been opened. 

Country rock .—The Lightfoot mine is situated in an area of greenstone 
schists, which under the microscope are seen to be igneous in origin. The 
strike of the schistosity is northeast and southwest and the dip is steeply 

aHamilton, J. R., The Natural Wealth of Virginia, Harper's Magazine, 1865, 
vol. xxxii, p. 41. 



242 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

toward the northwest. The schists show little variation in texture or color, 
being usually dark green and fine-grained. Megaseopically, chlorite and 
epidote with occasional eyes and stringers of quartz and calcite are the 
most prominent minerals; and when the powdered rock is tested with a 
magnet it is found to contain an abundance of fine-grained magnetite. In 
addition to these minerals, plagioelase feldspars, hornblende and some 
titanium minerals can usually be recognized under the microscope. These 
rocks are described in greater detail on pages 49-51. A little pyrite, often 
more or less cupriferous, and the secondary copper mineral—malachite— 
were found in the schist at several places within a mile or less of the mine. 
Where the rocks have been much fractured the openings are filled with 
quartz, epidote, calcite, or mixtures of these, forming irregular veinlets. 
In places magnetite appears to have undergone a similar concentration and 
may be picked up on the surface in pieces the size of hen’s eggs or even 
larger. 

Ore-deposit .—According to Oredner, the vein was 4 to 5 feet wide near 
the surface, and consisted of iron oxide; below this capping, iron pyrites 
was encountered and continued for about 20 feet before chalcopyrite began 
to appear; and in the lower workings he found a coarse-grained mixture 
of iron and copper sulphides, which carried 11 per cent, copper." The 
lower workings of the present opening are said to show an irregular vein, 
which in places consists of roughly parallel veinlets, ranging from several 
feet in width down to an inch or less, and the walls are rather sharply 
defined. 

The waste rock found on the dump shows that the country rock in the 
immediate vicinity of the vein has been greatly crushed and fractured. 
Extensive epidotization has taken place along the fractures, and where 
openings had been formed they are usually filled with quartz containing 
crystals of epidote and sometimes considerable calcite. The veinlets 
formed in this way are usually 4 or 5 inches in width or less. In places 
vug-like openings occur lined with quartz and crystals of epidote. Pyrite 
and chalcopyrite are occasionally present in the wall rock as well as in the 
veinlets, and where these minerals have been long subjected to oxidation 
the green stain of malachite is usually prominent. All the rock contains 
more or less magnetite, and fine-grained masses of this mineral, weighing 
several pounds, were noted, in which the only impurities that could be 
detected megaseopically, were a little quartz, epidote, and occasionally 

oCredner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1869, vol. vii, p. 58. 



DESCRIPTION OF COPPER MINES AND PROSPECTS. 243 

chalcopyrite. A piece of the greenstone schist found on the dump con¬ 
tained a veinlet or segregated area of white feldspars, which wefe 0.5 to 1 
cm. in diameter, and showed fine albite twinning. Chalcopyrite and 
magnetite were plentifully distributed between the feldspars, and in places 
along their cleavage planes, in a way that indicated a later origin for the 
ore minerals. 

The best ore seen at the mine consisted essentially of a mixture of 
pyrite and chalcopyrite, but most of the ore found on the dump was com¬ 
posed chiefly of pyrite, slightly cupriferous, with a little quartz, chlorite, 
and epidote visible to the naked eye. Assays of the ore are said to show 
good values in gold, and Hamilton states that native copper was found in 
some of the ore, but this could not be confirmed. 

The Bumpus Property. 

At several other localities in this vicinity a little prospecting for copper 
has been carried on. The old Bumpus place lies northwest of the Light- 
foot mine on the opposite side of Slate River, and here a 20-foot shaft 
Avas sunk at a point where much limonite and magnetite were found on 
the surface. The shaft Avas opened in soft chloritic slate, and no copper 
ore seems to haA r e been found. 

The Ford Property. 

On the Ford property, about three-quarters of a mile soutliAA'est of the 
Lightfoot mine, a A-ein is said to haA^e been discoA'ered in 1835, which aatis 
rich in gold at the surface, but at a depth of 4 or 5 feet copper pyrite 
became so plentiful as to interfere with amalgamation, and the work Avas 
abandoned.® Later, a 60-foot shaft AA'as sunk to strike the A’ein at another 
point, but a few lenticular quartz concretions containing copper pyrite 
seem to be all that AA'as found. Credner mentions two small Aherns that 
were exposed by open cuts, the gangue being quartz, while iron and copper 
pyrite, and a little free-gold AA'ere present. 6 

The Anaconda Mine. 

Location .—The Anaconda mine is located near Eldridge Mill, and is 
about 3Y2 miles west of Johnson and 5 miles north of Dilhvyn, stations 
on the Buckingham Branch of the Chesapeake and Ohio Railway. 

History. — The Anaconda mine was formerly knoAvn as the Eldridge 
mine, and about 1903 it Avas under development by the Q. Q. Copper Co., 


aHamilton, J. R., Op. cit. 
&Credner, H., Op. cit. 



244 GEOLOGY OF THE GOLD BELT IN THE JAMES FIVER BASIN. 

which sank a shaft to a depth of approximately 60 feet. About 1905 the 
United States Mineral Co. did a little development work, and in 1910 the 
shaft was again pumped out, but almost immediately allowed to refill with 
water. The shaft is now said to have a depth of nearly 75 feet, and near 
the bottom, a short drive extends in a northeast direction. While work 
was going on, 3,300 pounds of ore running 10% per cent, copper were 
shipped to the smelter at Norfolk. 

Descriptive geology .—The ore-deposit lies in the same belt of green¬ 
stone schists in which the Lightfoot mine is located and the country rocks 
are, for the most part, similar to those already described. About 400 yards 
northeast of the mine several openings have been made exposing amphibole 
asbestos, some of the fiber being 7 or 8 inches in length, talc, and chloritic 
schists carrying needle-like crystals of actinolite. The rock found on the 
dump is practically the same as that at the Lightfoot mine. It is mostly 
a dark green, fine-grained chloritic schist, in which considerable epidote 
is present especially along fractures. A little calcite in small crystals is 
in places scattered through the rock mass, but no veinlets or large masses 
were seen. Fine-grained magnetite and occasional grains of pyrite and 
chalcopyrite were noted. In a thin section (Spec. 352) the minerals 
present, in the order of their relative abundance, are quartz, chlorite, 
epidote and zoisite, hornblende, calcite, plagioclase feldspar, pyrite, and 
titanite. The hornblende occurs in dark green, needle-like prisms largely 
altered to chlorite. The calcite frequently shows multiple twinning. It 
is apparently a basic igneous rock which has been extensively altered by 
pressure and hydrometamorphism. 

Specimens of the ore seen at the mine consist essentially of pyrite and 
chalcopyrite intercrystallized with quartz as gangue. A little bornite, 
probably secondary, was noted in places, and the carbonates azurite and 
malachite, derived from the sulphides, are also present, usually along 
fractures in the rock. The vein is said to be several feet wide in places, 
but elsewhere pinches to almost nothing. 

Genesis of Ores at the Lightfoot and Anaconda Mines. 

Many basic igneous rocks in different parts of the world have been 
found to contain small quantities of copper. Rocks of this type are 
common throughout much of the Blue Ridge region in Maryland and 
Virginia where there are basaltic lava flows, which, since their extrusion, 
have been greatly altered, with the production of secondary minerals, 
especially chlorite and epidote. As a result of the metamorphic changes 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 245 

which these rocks have undergone, the small amount of copper originally 
disseminated in the rock has, in places, been locally concentrated along 
joints and fractures, giving rise to copper deposits which have become 
known as the Blue Ridge or Catoctin type.® 

The ores at the Lightfoot and Anaconda mines are similarly situated 
in an area of altered basic rocks, igneous in origin; and copper-bearing 
minerals have been found occurring in the country rock in small quantities 
at a number of widely separated localities; but there is a marked difference 
between the ore-deposits in this area and those of the Blue Ridge type, 
especially in the character of the ore-minerals. In the Blue Ridge type of 
deposit, the ore-minerals are chiefly cuprite and native copper, the latter 
often as nucleal masses surrounded by cuprite, together with small amounts 
of azurite and malachite, and, very rarely, of copper sulphide. 6 At the 
Buckingham County mines the copper minerals are chiefly sulphides, mala¬ 
chite and azurite being present only to a limited extent, and where they 
have been clearly derived from the sulphides, while cuprite and native 
copper are rare if they occur at all. 

Both the Lightfoot and the Anaconda mines were inaccessible when 
the writer visited the district in 1910, and it would be impossible to make 
definite statements in regard to the genesis of the ore-deposits without 
more detailed examination, but it seems probable that the copper, which 
they contain, was originally disseminated through the surrounding rocks, 
and that it has been concentrated by the circulation of meteoric waters, at 
favorable points in openings formed by local fracturing. Some of the 
principal facts in favor of this hypothesis may be summed up as follows: 

(1) Copper-bearing minerals are present in small quantities in the 
country rock at considerable distances from the ore-deposits, and there¬ 
fore the country rock furnishes a possible if not the probable source of the 
ore-minerals. 

(2) The principal gangue minerals in the ore-deposits—quartz, 
epidote, calcite, and magnetite—are important constituents of the country 
rock, the difference being one of relative proportions only, and no minerals 
have been observed in the ores that have not been found in the country 
rock. Therefore the country rock furnishes a possible if not the probable 
source of the gangue minerals. 

aWeed, W. H., Types of Copper Deposits in the Southern United States, Trans. 
Amer. Inst. Min. Eng., 1900, vol. xxx, p. 498. 

bWeed, W. H., Copper Deposits of the Appalachian States, U. S. Geol. Survey, 
Bull. No. 455, p. 14. 


9 




246 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


(3) The fracturing of the rocks furnished a channel for the circula¬ 
tion of concentrating solutions and openings for the deposition of the ore- 
deposits. 

(4) The extensive formation of hydrous from anhydrous minerals, 
which is the chief feature in the metamorphism of the great mass of rocks 
in this immediate area, necessitates the introduction of much water, and 
circulating water is an agent sufficient to account for the transportation 
and concentration of the minerals forming the ore-deposits. 

(5) The extensive formation of epidote adjacent to fractures in the 
immediate vicinity of the ore-deposits is evidence of the circulation of 
solutions at these points. 

The difference between the Buckingham copper deposits and those of 
the Blue Ridge type may possibly be due to the formation of the former 
at a greater depth, and to the fact that the greenstone schists in this district 
are, as a whole, more dense, closer textured and without the amygdaloidal 
cavities and similar openings common in much of the Catoctin schist. As 
originally deposited, these ores probably consisted chiefly of cupriferous 
pyrite, and in that case most of the chalcopyrite owes its origin to secondary 
enrichment. It is doubtful whether the copper values will continue to 
any considerable depth from the surface, and the writer does not believe 
that these deposits will prove to be very extensive or of much economic 
value. 

THE NEW CANTON MINES. 

The New Canton ore-body has been exposed by a series of openings, 
consisting chiefly of shafts and tunnels, which begin at a point half a mile 
south of New Canton and extend in a straight line for a distance of a mile 
in a southwesterly direction. (See map, fig. 2, p. 17.) 

HISTORY. 

While the New Canton mines have never been of much economic im¬ 
portance, they have had a long and varied history, having been first worked 
for iron, later for copper, and more recently prospected for pyrite. The 
gossan or oxidized ore, which consists principally of limonite and forms 
the surface cap of the sulphide bodies, first attracted attention; and 
according to Prof. Rogers, iron was manufactured from the Buckingham 
ore as early as the Revolutionary War. However, very little mining was 
done until some time in the early 30’s, when a charcoal furnace, known as 
the Bear Garden or Dean furnace, was built about half a mile south of 
New Canton. In his ‘‘Report of the Geological Reconnoissanc-e of the 


DESCRIPTION' OF COPPER MINES AND PROSPECTS. 247 

State of Virginia, 1835,” Bogers states that, “the limestone on the western 
edge of the county furnishes the flux employed in the smelting of this ore, 
which, under the superintendence of Mr. Dean of New Canton, is now 
conducted on a scale of such extent as to give a weekly product of between 
thirty and forty tons of pig metal, much of which is of a superior quality.”® 
Piles of slag indicate that there was another furnace located less than a 
mile southwest of New Canton. Mining was entirely confined to surface 
cuts along the outcrop, and as these became deeper pyrite began to appear 
and rapidly increased until the percentage of sulphur became prohibitive. 
Bogers says that fine specks of gold were discovered in the cinder or slag 
at these works. Iron ore was also hauled from Ore Bank, three-quarters 
of a mile southeast of Arvonia, and smelted at the New Canton furnace, 
but in 1840 the furnace was abandoned and no further work seems to have 
been done until prospecting for copper was started. 

The Johnson Mine. 

At the Johnson mine, formerly known as the Staples mine, which is 
located three-quarters of a mile west of south from New Canton, a 78-foot 
shaft was sunk by Mr. Staples, who mined and shipped 780 tons of ore 
averaging 8 per cent, copper. After this the property was leased and 
operated by White & Walters for a period of 2 or 3 years, beginning about 
1891. Several shipments were made and $4,000 is said to have been 
realized from the copper in the ore. About 1903, the Johnson Mining Co. 
bought the property and began development work. A vertical shaft, 
started on top of the hill, was sunk to a depth of 278 feet, and an adit 
was driven from the creek northwest to connect with the shaft. There are 
3 levels in the mine and the total length of the drives is said to he 1,000 
feet or more, but little or no mining was done. 

The McKenna Mine. 

The McKenna mine joins the Johnson mine on the northeast, and is 
situated a little over half a mile south of New Canton. It was first pros¬ 
pected for copper by J. P. McKenna about 1895, and in 1906 the A irginia 
Copper Co. began to develop the property. A 53-foot shaft was sunk at 
the foot of the hill in the lowlands near the creek, and two short drives 
opened from it, but work was stopped in 1907, and has not been resumed 
since that time. 


aRogers, W. B., Geology of the Virginias, p. 80. 



248 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

The Hudgins Mine. 

The Hudgins mine, located 1.5 miles southwest of New Canton, was 
opened about the same time that the other two mines were being prospected. 
A shaft was sunk to a depth of about 70 feet, which seems to have been 
the extent of the development work. When visited by the writer in 1911 
the shaft had partly caved and was inaccessible. 

The Margaret Mine. 

The Margaret or Terrell mine adjoins the McKenna mine and is 
situated on the west side of Phelps Creek about half a mile south of New 
Canton. This property was first opened in April of 1910, when a shaft 
was sunk to a depth of 80 or 90 feet in search of a pyrite deposit that could 
be profitably worked. When examined by the writer in the summer of 
1911 the shaft had been pumped out, and preparations were being made 
to sink it deeper. 

GENERAL DESCRIPTION OF THE GEOLOGY. 

The bluffs along James River and Phelps Creek furnish an almost 
perfect section across the rock strata in which the New Canton mines are 
situated, and this section, together with the mine openings and occasional 
outcrops elsewhere in the vicinity, make it. possible to study these ore- 
deposits in somewhat greater detail than can be done in the case of most of 
the veins that occur in this area. 

A 

The New Canton sulphide deposits occur in a schist, sedimentary in 
origin, which, a few hundred yards west of the mines, is interbedded with 
a schistose quartzite. East of the mines, stretches the area of intrusive 
granite (chiefly granodiorite), but between the granite and the ore- 
deposits is a belt of hornblendic schists 700 to 900 yards wide, part of 
which represents a basic border facies of the granite, while the rest is 
probably sedimentary in origin, though intensely metamorphosed by the 
intrusion of the great igneous magma. It is not possible to draw' with 
certainty a line between the hornblende schists that are igneous, and those 
that are chiefly sedimentary in origin, for the former as well as the latter 
have been greatly changed by metamorphism under mass-mechanical con¬ 
ditions; and the difficulty is increased by the fact that there are dikes 
or apophyses from the igneous mass, interleaved with metamorphic rocks 
wdiich are apparently sedimentary in origin. The series of rocks 
encountered in passing across this contact is described in detail on pages 
107-112, and therefore they will be discussed here only in so far as it is 
necessary to bring out their relations to the ore-deposits. 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 


249 


Northeast of the mines, at a distance of 300 to 400 yards, the country 
rock is a dark gray knotted slate, or schist, containing numerous rounded 
pseudophenocrysts of biotite averaging 1 to 1.5 mm. in diameter. These 
crystals of biotite are dark brown to black in color and have no regular 
orientation relative to the schistosity of the fine-grained slaty ground-mass 
in which they are embedded. Small reddish-brown garnets may also be 
present but are not plentiful. In the ground-mass quartz, sericite, and a 
few scattered grains of magnetite, are the only minerals distinguishable 
megascopically, but under the microscope biotite, chlorite, and rarely 
plagioclase feldspar, may also be identified. 

Passing eastward toward the contact, the biotite crystals gradually give 
place to garnets, and at the same time the schists become slightly coarser 
grained and lighter in color. The difference in color may be due to 
difference in composition, but is probably, in part, caused by increased 
development of sericite and a greater concentration of the iron in certain 
iron-bearing minerals. Small crystals of pyrite are abundant in the schists 
near the ore-bodies, which have no definite walls or boundaries. The ore 
is found in white to light gray, garnetiferous schists which, aside from the 
impregnating pyrite, are composed essentially of sericite and quartz, 
though chlorite is usually present and sometimes in considerable quantity. 
Plagioclase feldspar occurs to a limited extent, and occasional crystals of 
hornblende begin to make their appearance. 

The ore-minerals, chiefly pyrite, occur irregularly disseminated 
through the quartz-sericite schist, and where most abundant form irregular 
stringers or lenses parallel to the schistosity. The mineralized schists are 
cut by occasional small lenticular veins of quartz, carrying more or less 
feldspar, but as a rule they contain little pyrite, though the latter, in 
places, is concentrated along the walls of the veins. 

The hornblende schists on the east side of the ore-bodies are usually 
fine-grained but vary somewhat in composition and texture in passing 
across their strike. In the vicinity of the ore-deposits, and for some 
distance along their line of strike where they have not been found, there 
is usually much pyrite in the hornblende schists. Within 100 or 150 yards 
of the ore-bearing schists, apophyses of the granite occur as intrusions in 
the hornblendic rocks, and, at least in places, there is a narrow band 
along their contacts composed essentially of chlorite and garnets. The line 
drawn on the map (fig. 2) to represent the approximate contact between 
the rocks that are igneous and those that are sedimentary in origin, is 
located on the basis of the structural relations and appearance of the rocks 


250 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

in the field, rather than on any difference in texture or mineral composi¬ 
tion, and while it is unlikely that there are important masses of altered 
sedimentary rocks on the east side of the line, there are known to be 
apophyses or dikes on the west of it. Much vein quartz occurs as small 
pieces in the soil derived from the sedimentary schists in the vicinity of 
their contact with the area of igneous rocks on the east. 

The ore-body is apparently continuous for a distance of more than a 
mile along its course. It is not exposed in the section furnished by the 
bluffs along Phelps Creek, although near the line of its strike much 
pyrite is present in the schists. Southwest of the Hudgins mine, outcrops 
are not as plentiful, and it is impossible to say how much farther the ore- 
body extends in that direction. A little prospecting is reported at several 
places, but nothing of value has been discovered. 

DETAILED DESCRIPTION OF THE ORE AND INCLOSING ROCK. 

The Margaret Mine. 

The outcrops of the ore-bearing rocks are stained with limonite and more 
or less porous from the oxidation of sulphides. In places directly above 
the ore-body there are large outcrops of gossan, consisting of dark brown, 
porous limonite containing comparatively little silica, and only occasional 
fragments of decomposed schist. At the Margaret mine, the dark bluish- 
gray schist with phenocrysts of garnet and biotite occur less than 100 feet 
west of the shaft started in the limonite capping, and pieces of hornblende 
schist were found lying on the surface only a short distance toward the 
east. Intermingled with the hornblende schist were found a few pieces 
of fine-grained quartzite, carrying irregular dark green crystals of horn¬ 
blende and light greenish-brown needles of sillimanite. Pieces of rock 
were also found which appear to be intermediate in mineral composition 
between the hornblende schists and the quartz-sericite-chlorite schists. 

The shaft at the Margaret mine was sunk on top of a ridge about 30 
to 40 feet above the creek and the limonite ores continued to a depth of 
28 or 30 feet, which is approximately the water level, before pyrite was 
encountered. Pyrite more or less cupriferous is the chief ore-mineral 
from this point down, but at a depth of about 55 feet it is accompanied 
by some chalcopyrite and bornite. The copper sulphides are not very 
plentiful and seem to be confined to a zone having a vertical thickness 
of 4 or 5 feet. In the bottom of the shaft which is about 90 feet deep, 
pyrite, slightly cupriferous, is the only ore-mineral. Fractures or joints 
in the rocks are frequently coated with hyalite, usually white but some- 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 


251 


times light green from copper stain. The strike of ,the schistosity is about 
U. 30° E. and the dip practically vertical. All the schists exposed in the 
shaft are more or less impregnated with sulphides, but the distribution is 
very irregular, the areas of greatest concentration frequently having the 
appearance of veinlets of pyrite. The schists are cut by occasional small 
lenticular veins of quartz and feldspar ranging up to 5 or 6 inches in width. 
The sketch shown in fig. 23 roughly illustrates the structural relations 
of the ore-deposit and the distribution of the pyrite. 


N. W.-- -► s. E. 



SCALE 

_2_3 Feet 

- r ^3 


Fig. 23.—Diagrammatic section showing quartz-feldspar lenses and distribution of 
sulphides in schist at the Margaret Mine. Q, quartz-feldspar lens; 8, schist 
with a little disseminated pyrite; P, chiefly pyrite. 

The richest ore consists of 80 or 90 per cent, pyrite, a little white 
sericite, scattered pink garnets 1 to 1.5 mm. in diameter, a few small 
flakes of chlorite, and a little quartz. A thin section for microscopic 
examination was made from a piece of schist (Spec. 312-C) carrying about 
60 per cent, pyrite. In the hand specimens the rock appears to consist 
almost wholly of slightly cupriferous granular pyrite (1.5 to 2 mm. in 
diameter) and white sericite, with only a few small pink garnets. The 
distribution of the sulphides is closely related to the schistosity of the rock. 




































































































































































































































GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


252 


Near joint planes the sulphides have a dark coating and the white sericite 
is stained green by the presence of a small amount of copper. Under the 
microscope the smaller crystals of pyrite frequently show cubical form, but 
the larger masses have irregular outlines. The sericite is mostly oriented 
parallel to the schistosity, but many of the flakes look as though they 
had been pushed aside by the pyrite. Quartz is more plentiful in the thin 
section than one would suppose from a megascopic examination of the 
rock. It shows marked optical distortion and slight granulation from 
crushing, and contains occasional liquid and gaseous inclusions. A little 
magnetite is present in small grains and is usually closely associated with 
pyrite. 

Another specimen (316) of schist, showing the contact with a quartz- 
feldspar stringer which cuts across the cleavage and has narrow veinlets 
of quartz branching off parallel to the schistosity, is a light gray, close- 
textured rock composed of fine-grained quartz, sericite, chlorite, a little 
magnetite, and numerous red garnets ranging up to 1 mm. in diameter. 
Pyrite is plentiful but not abundant, occurring in grains and small 
lenticular masses elongated in the direction of schistosity; and while 
disseminated throughout the rock appears to be slightly more concentrated 
near the quartz veinlets. Under the microscope the quartz grains show ir¬ 
regular interpenetrating outlines and wavy extinction. The flakes of sericite 
and most of the light green chlorite are oriented parallel to the schistosity. 
The garnets are very ragged in outline and micropoikilitic in texture from 
numerous inclusions of quartz. In places they show slight alteration to 
chlorite. Plagioclase feldspars are also present and the minerals magnetite 
and pyrite are plentiful, frequently showing a close association, with pyrite 
occurring as inclusions in the magnetite or with the latter surrounded by 
the former. 

The quartz-feldspar veinlets range up to 6 inches or more in width, 
and are composed essentially of coarsely crystalline quartz, varying from 
white and translucent to clear and glassy, with more or less feldspar in 
angular crystals, having sharp straight outlines, ranging up to 1 cm. or 
over in diameter, and white to light yellow in color. In portions of the 
veinlets feldspar constitutes 10 per cent, or more of the mass while else¬ 
where it is practically absent. The feldspar crystals occur throughout the 
vein but are more plentiful near the walls and in places extend for a 
fraction of 1 cm. into the enclosing schists. Small masses of chlorite and 
garnet, probably representing inclusions of the country rock, are occasion¬ 
ally present. A little pyrite occurs in the central portions of the veinlets, 


DESCRIPTION - OF COPPER MINES AND PROSPECTS. 


253 


usually along cleavage planes or contacts between feldspar and quartz, 
but most of it is found near the walls and is yet more abundant in the 
enclosing schists. In thin section (315) under the microscope, the quartz 
shows some granulation and marked undulatory extinction, but the 
feldspars, aside from a slight warping of the cleavage planes, which is 
visible in the hand specimen, show no pressure effects. The feldspar is a 
soda-lime plagioclase, chiefly oligoclase-andesine, and usually shows 
multiple twinning after the'albite law, though this appears to be absent in 
places.® Liquid and gas inclusions, usually arranged in rows or planes, 
are plentiful in the quartz and occur to a lesser extent in the feldspar. 

The McKenna Mine. 

At the McKenna mine the gossan is exposed in the side of the bill 
just above the shaft, and apparently grades into the enclosing schists. It 
is said to be only about 8 feet deep in the shaft, which is located not far 
from the creek and fills with water almost to the surface. Descriptions 
of the ore-body exposed by the underground workings, and the rock lying 
on the dump, indicate that the deposit is similar in every way to that at 
the Margaret mine. It is reported that “peacock” copper ore was struck 
in the shaft about 35 feet from the surface, where it was about 8 feet wide 
and 6 feet thick. The walls of this secondary copper deposit were fairly 
well defined, but the large masses of pyrite graded into the country rock 
without definite walls. 

A specimen obtained by Dr. Maynard from the bottom of the shaft, 53 
feet from the surface, is darker colored and more chloritic than most of 
the rock found on the dump or in this vicinity. It is a dark green foliated 
schist in which chlorite, quartz, biotite, garnet, pyrite, and magnetite are 
easily distinguished megascopically. In thin section (Spec. 6) plagioclase 
feldspars can be identified, but as they closely resemble the quartz in index 
of refraction and do not always show twinning, it is impossible to estimate 
their relative abundance, though the quartz is probably much in excess. 
Part of the chlorite gives evidence of its derivation from biotite. A little 
sericite is also to be seen and a few light brown prismatic crystals, probably 
of hornblende. Pyrite is abundant and magnetite plentiful, the two 
minerals being closely associated, with pyrite usually surrounding the 
magnetite. 

a A specimen of this feldspar was submitted to Dr. E. S. Larsen, Jr., for deter¬ 
mination by the immersion method. He identified the feldspars as albite-oligoclase 
to oligoclase-andesine and states that the fresh and dominant feldspar is oligoclase- 
andesine. The maximum and minimum indices of refraction are: 

Of = 1.535 ± 0.003 to 1 . 541 ± 0.003 

T = 1 . 542 ± 0.003 to 1 . 549 ± 0.003 



254 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 


Some of the rock on the dump contains a little hornblende and probably 
represents the first stage of the gradation into hornblende schist. It is a 
light gray schist (Spec. 34) with a greenish tinge, consisting of fine¬ 
grained quartz, chlorite, sericite, garnets about 1 mm. in diameter, small 
grains of magnetite, and much disseminated pyrite, which is partly 
arranged in irregular planes parallel to the schistosity. The hornblende 
which is not plentiful occurs in dark green crystals ranging up to 2 or 3 
mm. in diameter. Examined under the microscope, the smaller garnets 
have well-defined outlines but the larger ones are usually ragged, and all 
of them contain included grains of quartz. The magnetite is disseminated 
in grains and small angular masses showing more or less distinct crystal 
outline. Pyrite is frequently in contact with magnetite and often occurs 
in narrow planes or lenses parallel to the schistosity. Small plagioclase 
feldspars and dark green prismatic crystals of hornblende, with a few 
grains of titanite, and small inclusions of apatite and zircon, make up the 
minor accessories. 

About 50 yards southeast of the McKenna shaft, a small diabase dike 
outcrops, but could not be traced any distance. The strike is probably 
northeast and southwest. It is a medium-grained, dark gray rock with 
ophitic texture easily recognizable in the hand specimen, and twinning can 
be seen on the feldspars with the aid of a pocket lens. Pieces of rock found 
on the dump indicate that a very fine-grained diabase dike, which in places 
is only l 1 /* inches wide, was encountered in the underground workings. 

The Johnson Mine. 

At the Johnson mine, the gossan may be seen outcropping in the road 
100 yards south of the shaft, and there is much vein quartz lying on the 
surface in the same vicinity. A short distance north, there are outcrops 
of the same knotted schist found on the east side of the ore-body wherever 
there are exposures. This rock was also encountered in the underground 
workings, and a thin section was made from a piece of the schist (Spec. 
319-A) found on the shaft dump. It is a dark gray, thinly foliated schist 
with the folia wrinkled by numerous small pseudophenocrysts of garnet 
and biotite around which they are folded. The garnets are much more 
plentiful than the biotite crystals, and there is also a little pyrite. Under 
the microscope the.biotite crystals are seen to contain numerous included 
grains of quartz and in a few instances the flakes are bent or curved, giving 
the mineral an undulatory extinction. They have no uniform orientation. 
The ground-mass is composed essentially of quartz and sericite with a little 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 


255 


chlorite, biotite, and very rarely plagioclase feldspar. The quartz occurs 
in elongated grains interleaved with fine shreds of sericite, all being 
perfectly oriented parallel to their greatest dimension. Flakes of sericite 
in the same vicinity extinguish together except where the folia are bent 
around the pseudophenocrysts, and there they look as though they had 
been pushed aside by the mineral in its growth, forming lenticular eyes, 
with quartz usually filling the ends of the lenses. Some of the eyes 
contain two crystals instead*of one, though this is not common. A similar 
rock (Spec. 307) in which the eyes are formed chiefly of biotite instead 
of garnet, is found at a somewhat greater distance from the granite. It is 
described on pages 32-33. 

Hornblende schist outcrops in the road less than 100 feet south of 
the gossan, and a microscopic slide (Spec. 458) was made from some of 
the rock obtained within 200 feet. In the hand specimen it is a fine¬ 
grained, dark green rock, close-textured and slightly schistose, composed 
for the most part of hornblende, quartz, and chlorite. Under the micro¬ 
scope the rock is distinctly schistose because of the approximate orienta¬ 
tion of the hornblende. This mineral is dark green in color, ragged in 
outline, and only occasionally contains inclusions of the other minerals. 
The hornblende constitutes about 75 per cent, of the rock mass. Irregular 
grains of quartz, chlorite, partly if not wholly derived from hornblende, 
a little plagioclase feldspar, and a few grains of magnetite make up the 
remaining constituents. In the absence of chemical analyses it is impossible 
to say whether this rock is igneous or sedimentary in origin, but the 
manner in which it is interbedded with other schists varying slightly in 
composition, leads the writer to believe that this schist is more likely 
derived from a sedimentary rock. 

At the mouth of the adit about 150 feet southeast of the Johnson shaft, 
a fine-grained, dark gray schist is exposed, in which quartz, chlorite, 
probably hornblende, magnetite, and pyrite are the only minerals coarse 
enough for megascopic identification. A thin section (Spec. 319-B) was 
made from a similar rock found on the dump. In the hand specimen it is 
a fine-grained, compact rock, gray with a slightly greenish tinge. It is 
slightly banded and contains a little disseminated pyrite, but most of the 
minerals are too small for megascopic identification. Under the micro¬ 
scope it is seen to consist of quartz, hornblende, soda-lime feldspar, 
chlorite, and magnetite, the order given being that of relative abundance. 
The quartz occurs in clear grains showing no granulation and little optical 
distortion. Hornblende is present in ragged individuals with numerous 


256 GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

inclusions of quartz and magnetite, and varies in size up to nearly 1 mm. 
in length. The crystals are uniformly oriented parallel to the schistosity. 
Plagioclase feldspar (probably andesine) is plentiful, and usually shows 
albite twinning. The chlorite is light green in color and occasionally shows 
multiple twinning. Magnetite occurs in small irregular grains uniformly 
distributed throughout the slide. 

Another variety of hornblende schist found on the dump is coarser 
grained (Spec. 320-A). Megascopically it is a dark green schistose rock 
containing crystals of green hornblende 1 to 2 mm. in diameter, brown 
biotite, green chlorite, and occasional brown garnets. In thin section the 
hornblende is light green in color, very ragged in outline, and contains 
numerous inclusions of the other minerals, principally quartz. It shows 
extensive alteration to carbonate and chlorite. The biotite has strong 
absorption, changing from brown to pale brown or colorless, and in places 
it shows alteration to chlorite. Quartz and soda-lime feldspar (andesine) 
are present in small grains, partly as inclusions in the hornblende and 
partly filling interstitial spaces. The feldspars usually show albite 
twinning. Grains of titanite, magnetite, and occasional rutile needles 
make up the minor accessories. 

Descriptions of the ore-body by men who worked in the mine, and the 
material found on the dumps, indicate that the ore-deposits at the Johnson 
mine are essentially the same as at the mines previously described. The 
ore-body is said to dip toward the northwest at an angle of about 80°. In 
some of the ore found on the dump pyrite occurs mixed with pyrrhotite 
and a little chalcopyrite, the gangue minerals being a small amount of 
quartz and sericite. Fragments from quartz-feldspar veinlets are also 
present on the dumps. The copper ore that was mined and shipped from 
this property is said to have consisted chiefly of “rich black copper ore” 
(chalcocite) found a short distance below the water level, and little or no 
high-grade copper ore seems to have been found in the lower workings. 

The Hudgins Mine. 

The country rock at the Hudgins mine, as indicated by outcrops in 
the vicinity, is exactly the same as at the other mines described above, and 
there seems to be no essential difference in the character of the ore-deposit. 
The material found on the dump is not as heavily impregnated with 
sulphides as at the Johnson and McKenna mines, and most of the ore- 
bearing schist is much lighter colored. Some of the rock closely resembles 
the quartz-sericite schist at the London and Virginia and Buckingham 


DESCRIPTION OF COPPER MINES AND PROSPECTS. 


257 


mines. It is a fine-grained, white, lustrous schist in which quartz, sericite, 
and disseminated pyrite are the only minerals that can be identified with 
a pocket lens. Other pieces found on the dump are similar but contain a 
few scattered flakes of biotite. 

GENESIS OF THE NEW CANTON ORE DEPOSITS. 

The New Canton ores belong to that class of ore-deposits known as 
contact deposits, and it is believed that the sulphides which occur impreg¬ 
nating the schists near the contact were derived from the mass of intruded 
igneous rock that lies to the east. Acid igneous rocks on cooling give off 
a large amount of water in the form of highly heated vapor or gas, and 
this water may carry minerals in solution and deposit them where the 
conditions are most favorable. That this has been the mode of formation 
of the New Canton deposits is indicated by the facts, brought out in the 
detailed descriptions, which may be summarized as follows: 

1. The location of the ores in highly metamorphic schists close to 
their contact with an acid igneous intrusive. 

2. The extensive alteration of the ore-bearing schists with the pro¬ 
duction of sericite, chlorite, and garnet. 

3. The presence of lenses and veinlets of quartz and feldspar, which 
in places approach pegmatite in composition and appearance. 

4. The association of pyrite, chalcopyrite, pyrrhotite, and magnetite 
as the principal ore minerals. 

As has been stated elsewhere in this report, the intrusion of the granite 
(granodiorite) was accompanied by a partial segregation or concentration 
of the more basic minerals in the border portions of the cooling magma, 
and the extensive metamorphism of the sedimentary rock along the contact. 
The rocks nearest the granite possibly owe their alteration, which resulted 
in the production of hornblendic rocks, chiefly to heat and pressure, but 
the alteration of the schists at a somewhat greater distance from the 
contact, seems to have been due primarily to the heated vapors expelled 
from the cooling magma. This is indicated by the predominance of the 
anhydrous minerals, chiefly hornblende, in the rocks nearest the contact; 
while in the ore-bearing schists, such hydrous minerals as sericite and 
chlorite were extensively developed. The occurrence of masses of chlorite 
containing many large garnets, which even under the microscope show no 
alteration, is difficult to account for if the chlorite was formed entirely as 
a result of superficial agencies, and, moreover, the inclusions of country 
rock found in the quartz-feldspar veinlets are all altered to chlorite, biotite. 


258 


GEOLOGY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 




and garnet. The same solutions that altered the schists and formed the 
quartz-feldspar veinlets, deposited the sulphide ores, chiefly pyrite. Some 
chalcopyrite may have been deposited as a primary mineral at this time, 
but it seems probable that most if not all of the copper was originally 
deposited as cupriferous pyrite. The sulphides undoubtedly filled any 
openings that may have been present, and while the schist may have been 
injected with veinlets and stringers of pyrite, as with quartz and feldspar, 
most of the sulphide masses, even where purest, give evidence of formation 
through metasomatic replacement of the schist. 

The frequent association of pyrite and magnetite suggests that the 
latter was formed by the reducing action of pyrite, since siderite is a 
prominent constituent in some of the knotted slates a few hundred yards 
west of the contact. Van Hise has called attention to the development of 
magnetite from iron carbonate on an extensive scale where igneous rocks 
have been intruded into ferruginous sedimentaries, and gives the following 
chemical equation as the probable reaction by which the magnetite is 
produced 

2FeC0 3 + FeS 2 + 2H 2 0 = Fe 3 0 4 + 2H 2 S -f 2C0 2 

The hydrogen sulphide set free by the reaction would aid in the alteration 
of the schists by combining with the iron derived from the iron-bearing 
silicates, and it is not improbable that the light color of the ore-bearing 
schists is partly due to the formation of pyrite at the expense of the dark- 
colored, iron-bearing silicates. 

The primary ore consisting chiefly of pyrite, slightly cupriferous, with 
perhaps more or less chalcopyrite, had a very low copper content. The 
high-grade copper ore, such as that obtained at the Johnson mine a short 
distance below water level, owed its formation to concentration through 
meteoric agencies, of the copper originally present in the upper portion of 
the ore-body. Surface waters, entering the ore-body by means of small 
pores, cracks, and joints, carry oxygen and carbon dioxide in solution 
which react on the sulphides to form copper sulphate and other more or less 
soluble salts. The copper salts, being more soluble than the iron com¬ 
pounds formed, are mostly leached out and carried farther down, where the 
copper is reprecipitated by replacing iron in the fresh sulphides below. 
As a result of these reactions, oxides and carbonates of copper may be 
present in the upper, oxidized portion of the ore-body, while the rich 
sulphurets, such as chalcocite, bornite, and chalcopyrite, occur near the 

a Van Hise, C. R., A Treatise on Metamorphism, Monograph XL VII, L T . S. Geol. 
Survey, 1904, p. 838. 



DESCRIPTION OF COPPER MIXES AND PROSPECTS. 


251) 


water level, and in the deeper portions of the ore-body only the low-grade, 
primary sulphides are found. 

The practical absence of malachite, azurite, and copper oxide from the 
oxidized portion of these ore-deposits is probably due to the low copper 
content of the primary ores, the humid climate, and the long period during 
which the copper has been subjected to concentration. The ore-bodies 
originally extended much higher above the present surface, and part of the 
copper contained in the zone of secondary enrichment undoubtedly came 
from the upward extension of the deposits, which have been removed by 
erosion during the long period of time which has elapsed since the ores 
were first formed. 

COMPARISON WITH OTHER ORES OF THE DISTRICT. 

There is a marked resemblance between the New Canton ores and those 
at the London and Virginia, and Buckingham mines, the difference being 
chiefly in the relative proportion of the minerals present. At the latter 
locality the sulphides, which are apparently not as plentiful, occur chiefly 
as impregnations in a quartzite instead of a schist, the quartz-feldspar 
veinlets are more prominent, and the gold content is greater while that of 
copper is less. The New Canton type of deposit seems to represent one 
extreme of a gradational series, the typical gold-bearing veins of the 
district being at the other extreme, with the London and Virginia type 
intermediate between the two. At the New Canton mines the secondary 
ores were, in places, rich enough in copper to pay for their extraction, but 
these ores can not be expected to extend any great distance below the water 
level, and it is not believed that the copper content of the primary ores is 
sufficient to make them of value as a source of that metal. While in places 
high-grade pyrite occurs in the deposits, the greater portion of the ore- 
bodv contains a large amount of gangue material, and it is improbable 
that these mines could be profitably worked at the present time for their 
sulphur content alone. 


GEOLOGY OF THE GOLD BELT IN THE JAMES EIVER BASIN. 


260 


BIBLIOGRAPHY OF THE GOLD BELT IN THE JAMES RIVER BASIN. 

Ansted, D. T., The Alleghanies and the Gold District of Eastern Virginia, Third 
Chapter in Scenery, Science, and Art, London, 1854, pp. 277-293. 

Becker, G. F., A Reconnaissance of the Gold Fields of the Southern Appalachians, 
16th Ann. Rept., U. S. Geol. Survey, 1894-5, pt. iii, pp. 251-331. 

Campbell, J. L., The Virginia Gold Belt near the Richmond and Alleghany Railway, 
The Virginias, 1882, vol. iii, pp. 120-121. 

-. Geology and Mineral Resources of the James River Valley, Virginia, 

U. S. A., with Map and Geological Sections, New York, 1882, pp. 14-19, 
99-106, and 112. 

Clemson, T. G., and Taylor, R. C., The Gold Region of Virginia, Trans. Geol. Soc. 
Pa., 1835, vol. i, p. 309. 

Credner, H., Report of Explorations on the Gold Fields of Virginia and North 
Carolina, Amer. Jour. Mng., 1868, vol. vi, pp. 361, 377, 393, and 406-407; 
1869, vol. vii, pp. 9, 26-27, 42-43, 58, 72-73, and 105. 

Dale, T. N., Slate Deposits and Slate Industry of the United States, U. S. Geol. 
Survey, Bull. 275, 1906, pp. 111-115. 

Darton, N. H., Fossils in the “Archaean” Rocks of Central Piedmont, Virginia, 
Amer. Jour. Sci., 1892, vol. xliv, pp. 50-52. 

Editor, The. Reprinted from paper by “The Editor,” in the Richmond Enquirer, 
The Garnet and Moseley Mine, Virginia, The Mining Magazine, August, 
1853, No. 2, vol. i, pp. 164-167. 

Froehling, Henry, and Robertson, Andrew, A Hand-Book on the Minerals and 
Mineral Resources o’f Virginia, Prepared for the Virginia Commission to the 
St. Louis Exposition, Richmond, 1904, 159 pp. For gold see pp. 43-52. 

Genth, F. A., Contributions to Mineralogy, Amer. Jour. Sci., 2d ser., 1855, vol. xix, 
pp. 15-23; 1859, vol. xxviii, pp. 246-255. 

Hamilton, J. R., The Natural Wealth of Virginia, Harper’s Magazine, 1865, vol. 
xxxii, pp. 32-42. 

Harrison, Randolph, Hand-Book of Virginia, 4th ed., p. 50. 

Hen wood, Wm. Jory, Observations on Metalliferous Deposits, Trans. Royal Geol. 
Soc. of Cornwall, 1871, vol. viii. For notice of gold mines in Virginia see 
pp. 371-384. 

Hotchkiss, Jed, Virginia : A Geographical and Political Summary, Richmond, Va., 
1876, 320 pp. For gold see pp. 34-35. 

-. The Resources of the Virginias on and near the Proposed Route of the 

Richmond and Southwestern Railway, The Virginias, 1880, vol. i, pp. 90-93. 

-. The Tellurium Mine and Virginia Gold Mining, The Virginias, 1881, 

vol. ii, p. 85. 

Johnson, W. R., Some Observations on the Gold Formations of Maryland, Virginia, 
and North Carolina, Proc. Amer. Asso. Adv. Sci., 1850, vol. iv, pp. 20-21. 
(Discussed by W. B. Rogers, pp. 21-22.) 

Locke, A. G., Gold, Its Occurrence and Extraction, New York, 1882, pp. 182-190. 

Mauby, M. F., Physical Survey of Virginia: Her Resources, Climate, and Pro¬ 
ductions, Richmond, 1878, 143 pp. For gold see p. 38. 

Nitze, H. B. C., and Wilkens, H. A. J., The Present Condition of Gold Mining in 
the Southern Appalachian States, T^ans. Amer. Inst. Mng. Engrs., 1896, 
vol. xxv, pp. 661-796, 1016-1027. 

-. Gold Mining in North Carolina and Adjacent South Appalachian 

Regions, N. C. Geol. Survey, Bull. 10, 1897. 

Partz, A., Examinations and Explorations on the Gold Belts of the Atlantic States, 
The Garnet and Moseley Mines, Virginia, Mining Magazine, 1854, vol. ii, 
pp. 378-380. 

Pollard, Thomas, A Hand-Book of Virginia, Richmond, 1879, pp. 16-18, 20, and 
102; Ibid., 3d ed., Richmond, 1881, pp. 106-107, 120. 

- (The Gold Belt of Virginia.) In “Gold, Its Occur rence and Extraction,” 

by A. G. Locke, New York, 1882, pp. 182-190. 







BIBLIOGRAPHY. 


261 


Rogers, \\ m. B., Report of the Geological Reconnoissance of the State of Virginia, 
Made under the Appointment of the Board of Public Works, Richmond, 1836. 

Republished at Philadelphia, 1836. 

(See Geology of the Virginias.) 

-. Report of the Progress of the Geological Survey for the Year 1839, 

Richmond, 1840. 

(See Geology of the Virginias.) 

-. Report of the Progress of the Geological Survey for the Y T ear 1840, 

Richmond, 1841. 

(See Geology of the Virginias.) 

-. Geology of the Virginias. (A Reprint of Annual Reports and Other 

Papers on the Geology of the Virginias, Edited by Mrs. W. B. Rogers), 
New York, 1884. 

Silliman, B., Remarks on Some of the Gold Mines, and on Parts of the Gold Region 
of Virginia, Founded on Personal Observations Made in the Months of 
August and September, 1836, Amer. Jour. Sci. and Arts, 1837, vol. xxxii, 
pp. 98-130. 

Watson, Thomas L., Mineral Resources of Virginia, Lynchburg, Va., 1907, 
xxxi-f- 618 pp. For gold see pp. 549-567; Copper deposits of Buckingham 
County, pp. 500-502; The Buckingham-Fluvanna counties slate belt, pp. 
42-46. 

-. Granites of the Southeastern Atlantic States, Bull. 426, U. S. Geol. 

Survey, 1910, pp. 112-113. 

- and Powell, S. L., Fossil Evidence of the Age of the Virginia Piedmont 

Slates, Amer. Jour. Sci., 1911, vol. xxxi, pp. 33-44. 

Whitney, J. D., Metallic Wealth of the United States, Philadelphia, 1854. For 
Virginia, see pp. 119, 124-129. 

Williams, G. H., Anatase from the Arvonia Slate Quarries, Buckingham County, 
Virginia, Amer. Jour. Sci., 3d ser., 1891, vol. xlii, p. 431. 

List of Mining Reports and Prospecti. 

Johnson and Mathey, Prospectus of the Garnet and Moseley Gold Mining Co. 
(Not seen.) 

-. Prospectus of the London and Virginia Co. (Not seen.) 

-. Prospectus of the Garnet Gold Mining Co., of Buckingham County, Vir¬ 
ginia, New York, 1852. (Quotes from a letter by E. W. Johnson.) 

Snell, P. A., Report on the Belzora Mine. 

Virginia Gold, (A prospectus issued by the Hughes Gold Mining and Milling 
Company), Roanoke, Va., 1905. 

Miscellaneous Notes on Mines in the District. 

The following publications contain occasional notices of gold mines in 
Virginia and have been consulted in the preparation of this report: 

American Journal of Mining. 

Engineering and Mining Journal. 

Mineral Industry. 

Mineral Resources of the United States. 

Mining and Scientific Press. 

Mining Journal. 

Mining Magazine. 

Reports of the Director of the United States Mint on the Production of Precious 
Metals in the United States. 

United States Census Reports. 

The Virginias. 









INDEX 


Acknowledgments, 1. 

Age, diorite dikes, 84. 
granites, 54. 
greenstone schists, 49. 
ore-deposits, 233-234. 

Anaconda copper mine, 243-244. 
Descriptive geology, 244. 

History, 243-244. 

Location, 243. 

Anaconda gold mine, 50-51. 

Analyses, vein and wall rock, Young 
American Gold mine, 124. 
partial, ore, Tellurium mine, 
161. 

Analysis of tetradymite from Tellurium 
mine, 160. 

Anderson mine, 195. 

Description, 195. 

Location, 195. 

Annual production of gold, 200. 

Arvonia, 44-45. 

Atmore, Kent, and other properties, 142. 
Ayre tract, 20-21. 

Ballinger Creek, 52-53. 

Belzoro mine, 39, 139-141. 

Descriptive geology, 140-141. 

History, 139-140. 

Location, 139. 

Production, 141. 

Benton mine, 85, 152. 

Description, 152. 

Location, 152. 

Bertha and Edith mine. 38-39, 142-144. 
Description of veins and country 
rock, 143-144. 

History, 142-143. 

Location, 142. 

Bibliography of the gold belt in the 
James River Basin, 260-261. 

Big Byrd Creek, 35-36, 68-69, 79-80. 
Bluffs along James River. 45. 

Bondurant mine, 26, 192-195. 

Descriptive geology, 193-195. 

History, 192-193. 

Location, 192. 

Bowles bridge, 38. 

Bowles mine, 85, 175, 178-179. 

History and general description, 
175. 

Location, 175. 

Bremo Bluff, 16-18, 52. 

Buckingham County, mines in (See 
Mines in Buckingham County). 
Buckingham mine, 190-191. 

Geology of the ore-oody, 191. 
History, 190-191. 

Location, 190. 


Bula, 61. 

Bumpus property, 243. 

Burnett mine, 196. 

Descriptive geology', 196. 

History, 196. 

Location, 196. 

Busby mine, 146-147. 

Cambrian, 115, 116. 

Cambrian or post-Cambrian, 84-85. 

Diorite dikes, 84. 

Cartersville, 56. 

Cartersville area, 54-56. 

Detailed descriptions, 55-56. 

General description, 54-55. 
Carysbrook, 41-42, 45-46, 75-77. 
Carvsbrook bridge, 75. 

Classification, general, 14. 

Climate, 4. 

Collins mine, 141 
Columbia, 64-68, 86. 

Columbia area, 62-67. 

Detailed descriptions, 64-77. 

General description, 62-64. 
Comparison with other ores of the dis¬ 
trict, 259. 

Conglomerate, 40-42. 

Details of occurrences, 41-42. 
General character and distribution, 
40-41. 

Contact metamorphism, 106. 

Country rock, 176-177. 

Culture, 4. 

Cyanite schists, 26-29. 

Details of occurrences, 27-29. 

General character and distribution, 
26-27. 

Genesis, 24. 

Deposition of the ores, 221-222. 
Description of Anderson mine, 195. 

Belzoro mine, 152. 

Flood mine, 195. 
gangue minerals, 213- 
214. 

ore minerals, 214-215. 
ores, Morrow mine, 204- 
205. 

vein, London and Vir¬ 
ginia mine, 187-190. 
veins and country rock, 
Bertha and Edith 
mine, 143-144. 

Williams mine, 191-192. 
Description of copper mines and pros¬ 
pects, 241-259. 

Description of individual mines, 241- 
246. 

Anaconda mine, 243-244. 


(262) 




INDEX. 


263 


Descriptive geology, 244. 

History, 243-244. 

Location, 243. 

Bumpus property, 243. 

Ford property, 243. 

Genesis of ores, Light foot and Ana¬ 
conda mines, 244-246. 

Lightfoot mine, 241-243. 

Country rock, 241-242. 

History, 241. 

Location, 241. 

Ore-deposit, 242-243. 

New Canton mines, 246-259. 

Comparison with other ores of the 
district, 259. 

Detailed description of the ore and 
inclosing rock, 250-257. 

Hudgins mine, 256-257. 

Johnson mine, 254-256. 

McKenna mine, 253-254. 

Margaret mine, 248. 

General description of the geology, 
248-250. 

Genesis of the New Canton ore de¬ 
posits, 257-259. 

History, 246-248. 

Hudgins mine, 248. 

Johnson mine, 247. 

McKenna mine, 247. 

Margaret mine, 248. 

Types of copper deposits, 241. 
Description of individual copper mines, 
241-246. 

Anaconda mine, 243-244. 

Bumpus property, 243. 

Ford property, 243. 

Genesis of ores, Lightfoot and Ana¬ 
conda mines, 244-246. 

Lightfoot mine, 241-243. 

Descriptive geology, Anaconda mine, 244. 

Belzoro mine. 140- 
141. 

Bondurant m ine, 
193-195. 

Burnett mine, 196. 
London and Virgin¬ 
ia mine, 1S4-1S7. 
Morrow mine, 200- 
204. 

Moss mine, 145. 
Waller mine, 148- 
151. 

Descriptive geology’ and petrography, 13- 
87 ." 

Introduction, 13. 

Rocks igneous in origin, 47-87. 

Cambrian or post-Cambrian, 84-85. 
Diorite dikes, 84. 

Age, 84. 


Details of occurrences, 84-85. 
Benton mine, 85. 

Bowles mine, 85. 

Long Island Creek, 85. 
Palmyra, 84-85. 

Distribution and general char¬ 
acter, 84. 

General classification, 47. 
Pre-Cambrian, 47-53. 

Greenstone schists, 47-51. 

Age, 49. 

Details of occurrences, 49-51. 
Anaconda mine, 50-51. 

Hughes mine, 51. 

Lightfoot farm, 50. 

Palmywa, 51. 

Shores, 51. 

Slate River, 49-50. 
Quartz-feldspar porphyries, 51-52. 
Rhyolites, 52-53. 

Details of occurrences, 52-53. 
Ballinger Creek, 52-53. 

Bremo Bluff, 52. 

Palmyra, 53. 

Slate River, 52. 

General description and age re¬ 
lations, 52. 

Pre-Cambrian and Cambrian, 53-84. 
Granites, their associated pegma¬ 
tites and ho r n b1e n d e 
schists, 53-82. 

Age, 54. 

Cartersville area, 54-56. 

Detailed descriptions, 54-56. 
Cartersville, 56. 

Pemberton, 55-56. 

Stokes, 56. 

General description, 54-55. 
Columbia area, 62-77. 

Detailed descriptions, 64-77. 
Big Byrd Creek, 68-69. 
Cary’sbrook, 75-77. 
Carvsbrook bridge, 75. 
Columbia, 64-68. 

Fork LTiion, 73. 

Lantana, 69. 

New Canton, 71-72. 

Payne farm, 70-71. 

Rivanna Mills. 73-75. 
Stearnes, 72-73. 

Tabscott, 70. 

Trent farm, 71. 

Trenton Mills, 71. 

General description, 62-64. 
Elk Hill complex, 57-59. 
Detailed descriptions, 57-59. 
General description, 57. 

Gold Llill granite area, 77-80. 
Detailed descriptions, 78-80. 



264 


INDEX. 


Big Byrd Creek, 79-80. 
Hughes farm, SO. 

McGloam mine, 78-79. 
General description, 77. 
Granite at Greeley mine, 82. 
Introductory statement, 53-54. 
Pegmatite belt, 59-62. 

Detailed descriptions, 59-G2. 
Bula, 61. 

Dickey farm, 61. 

James River section, 59-60. 
Lantana, 61. 

Little Byrd Creek, 60-61. 
Other localities. 62. 
Shannon Hill, 61. 

General description. 59. 
Rosney granite area, 80-82. 
Porphyries, 82-84. 

Details of occurrences, 82-84. 
Distribution and general de¬ 
scription, 82. 

Triassic, 85-87. 

Diabase dikes, 85-87. 

Details of occurrences, 86-87. 
Columbia, 86. 

Dillwyn, 87. 

Grannison mine, 86. 

Other localities, 87. 
Pemberton, 87. 

Rocks sedimentary in origin, 14-47. 
General classification, 14. 

Ordovician, 39-46. 

Conglomerate, 40-42. 

Details of occurrences, 41-42. 
Carysbrook. 41-42. 

Long Island Creek, 42. 
Penlan, 41. 

General character and distribu¬ 
tion, 40-41. 

General statement, 39-40. 
Quartzite, 42. 

Schist, 42-43. 

Slate, 43-46. 

Details of occurrences, 44-46. 
Arvonia, 44-45. 

Bluffs along James River, 45. 
Carysbrook, 45-46. 

General character and distribu¬ 
tion, 43-44. 

Tuff, 43. 

Pre-Cambrian. 14-39. 

Cvanite schists, 26-29. 

Details of occurrences, 27-29. 
Trent farm, 28-29. 

Willis Mountain, 27-28. 
General character and distribu¬ 
tion, 26-27. 

Genesis, 27. 

Ferruginous quartzite, 19-22. 


Details of occurrences, 19-22. 
Ayre tract. 20-21. 

Other localities, 21-22. 

Scotia mine, 21. 

Webb tract, 19-20. 

General character and distribu¬ 
tion, 19. 

Garnetiferous quartzites, 22-23. 
Details of occurrences, 22-23. 
Lantana, 22-23. 

Stage Junction, 23. 

General character and distribu¬ 
tion, 22. 

General statement, 14-15. 

Gneisses, 36-39. 

Details of occurrences, 38-39. 
Belzoro mine, 39. 

Bertha and Edith mine, 38- 
39. 

Bowles bridge. 38. 

Young American mine, 38. 
General character and distribu¬ 
tion, 36-37. 

Genesis, 37. 

Hornblende-bearing quartzites, 23. 
Hornblende schists, 34-36. 

Details of occurrences, 35-36. 
Big Byrd Creek, 35-36. 
Lantana, 36. 

New Canton, 35. 

General character and distribu¬ 
tion, 34-35. 

Knotted schists, 29-34. 

Details of occurrences, 30-34. 
New Canton. 30-34. 

Stage Junction, 34. 
Strathmore, 34. 

Tellurium schists, 34. 

General character and distribu¬ 
tion, 29-30. 

Quartzite, 15-19. 

Details of occurrences, 16-19. 
Bremo Bluff. 16-18. 

London and Virginia mine, 
19. 

Tellurium mine, 18-19. 
General character and distribu¬ 
tion, 15-16. 

Quartz-sericite schist, 23-26. 
Details of occurrences, 24-26. 
Big Byrd Creek, 24. 
Bondurant mine, 26. 

Lantana, 24-25. 

London and Virginia mine, 
25-26. 

New Canton-Dillwvn road, 
25. 

Other localities, 26. 



INDEX. 


265 


General character and distribu¬ 
tion, 23-24. 

Genesis, 24. 

Triassic, 46-47. 

Detailed description, ore and inclosing 

rock, 250-257. 
Cartersville area, 
55-57. 

Columbia area, 64- 
77. 

contact phenomena, 
107-114. 

Elk Hill complex, 
57-59. 

Gold Hill granite 
area, 78-80. 
pegmatite belt, 59- 
62. 

Tellurium vein sys¬ 
tem, 157-172. 
veins and wall 
rock, 157-172. 
Young American 
mine, 122-139. 

James River section across granite 
contact, 107-112. 

Rivanna River, section across granite 
contact, 112-113. 

Veins, 113. 

Willis Mountain, 113-114. 

Details of occurrences, conglomerate, 40- 

42. 

evanite schists, 
' 27-29. 

diabase dikes, 86- 
87. 

diorite dikes, 84- 
85. 

ferruginous quartz¬ 
ite! 19-22. 
garnet’f’r’s quartz¬ 
ites, 22-23. 
gneisses, 38-39. 
greenstone schists, 
49-51. 

hornblende schists, 
35-36. 

knotted schists, 
30-34. 

porphyries, 82-84. 
quartzite, 16-19. 
rhyolites, 52-53. 
slate, 44-46. 
quartz-sericite 
schist, 24-26. 

Diabase dikes, S5-87. 

Details of occurrences, 86-87. 
Distribution and general character, 
85-86. 


Dickey farm, 61. 

Dillwyn, 87. 

Diorite dikes, 84. 

Age, 84. 

Details of occurrences, 84-85. 

Distribution and general character, 
84. 

Drainage, 3-4, 91-93. 

Elk Hill complex, 57-59. 

Detailed descriptions, 57-59. 

General description, 57. 

Equipment, Hughes mine, 1S1-182. 

Faulting, 100. 

Ferruginous quartzite, 19-22. 

Details of occurrences, 19-22. 

General character and distribution, 
19. 

Fleming mine, 151. 

History and description, 151. 

Location, 151. 

Flood mine, 195. 

Description, 195. 

Location, 195. 

Folding. 98-99. 

Ford property, 243. 

Fork Union, 73. 

Garnetiferous quartzites, 22-23. 

Details of occurrences, 22-23. 

General character and distribution, 

22 . 

General character and distribution: 
conglomerate, 40-41. 
evanite schists, 26-27. 
diabase dikes, 85-86. 
diorite dikes, 84. 
ferruginous quartzite, 19. 
garnetiferous quartzites, 22. 
gneisses, 36-37. 
greenstone schists, 47-49. 
hornblende schists, 34-35. 
knotted schists, 29-30. 
quartzite, 15-16. 
slate, 43-44. 

General conclusions as to the origin of 
the gold deposits, 231-232. 

General description, Cartersville a r e a , 

54-55. 

Columbia, area, 62- 
64. 

Elk Hill complex, 
57. 

geology, 248-250. 

geology, Young A- 
merican mine, 120- 
122 . 

Gold Hill granite 
area, 77. 

veins and country 
rock, Tellurium 
system, 155-157. 



INDEX. 


266 


General description and age relations, 
rhyolites, 52. 

General statement, Ordovician, 39-40. 

Pre-Cambrian. 14. 
Genesis, cyanite schists, 27. 
gneisses, 37. 

quartz-sericite schist, 24. 
Genesis of the deposits, 216-232. 
Deposition of the ores, 221-222. 

General conclusions as to the origin of 
the gold deposits, 231-232. 
Nature of the solutions, 217-219. 
Origin of the spaces occupied bv the 
veins, 222-231. 

Source of the material, 219-221. 
Genesis of the New Canton ore deposits, 
257-259. 

Genesis of ores, Lightfoot and Anaconda 
mines, 244-246. 

Genetic relations of the gold deposits, 
208-234. 

Age of the ore-deposits, 233-234. 
Genesis of the deposits, 216-232. 
Deposition of the ores, 221-222. 
General conclusions as to the origin 
of the gold deposits, 231-232. 
Nature of the solutions, 217-219. 
Origin of the spaces occupied by the 
veins, 222-231. 

Source of the material, 219-221. 
Introduction, 208-209. 

Previous theories, 208-209. 

Types of deposits. 209. 

Mineral composition of the veins, 209- 
216. 

Description of the gangue minerals, 

213- 214. 

Description of the ore minerals, 

214- 215. 

List of minerals in the gold veins of 
the James River basin area, 
211 - 212 . 

Summary, 215-216. 

Secondary enrichment, 232-233. 
Geography and history. 2-12. 

Climate, 4. 

Culture, 4. 

Drainage, 3-4. 

History, 5-9. 

Location, 2-3. 

Previous geologic work, 9-12. 
Production, 9. 

Soil, 4. 

Topography, 3. 

Geology, Anaconda mine, 244. 

Bondurant mine, 193-195. 
Buckingham mine, 191. 

Burnett mine, 196. 

Hughes mine. 182-183. 


London and Virginia mine, 
184-187. 

Morrow mine, 200-204. 

Snead mine, 180-181. 

Geology of veins and country rock, 
Hughes mine, 182-183. 

Gilliam mine, 195. 

Gold Hill granite area, 77-80. 

Detailed descriptions, 78-80. 

General description, 62-64. 

Gold Hill vein system, 176-179. 

Bowles mine. 178-179. 

Country rock, 176-177. 

Introduction, 176. 

McGloam mine, 177-178. 

Shaw mine, 178. 

Gold mines of the district, 118-208. 
Introduction, 118. 

Mines in Buckingham County, 183- 
207. 

Anderson mine, 195. 

Description, 195. 

Location, 195. 

Bondurant mine, 192-195. 

Descriptive geologyq 193-195. 
History, 192-193.'' 

Location, 192. 

Buckingham mine, 190-191. 

Geology of the ore-body, 191. 
History, 190-191. 

Location, 190. 

Burnett mine, 196. 

Descriptive geology, 196. 

History, 196. 

Location, 196. 

Flood mine, 195. 

Description, 195. 

Location, 195. 

Gilliam mine, 195. 

Greeley mine. 205-207. 

History, 205-206. 

Location, 205. 

Veins and country rock, 206-207. 
Hobson tract, 197. 

Lightfoot mine, 207. 

Gold veins, 207. 

History, 207. 

Location, 207. 

London and Virginia mine, 183-190. 
Description of vein, 187-190. 
Descriptive geology, 184-187. 
History, 183-184. 

Location, 183. 

Morrow mine, 198-205. 

Description of ores, 204-205. 
Descriptive geology, 200-204. 
History, 198-199. 

Location, 198. 

Placers, 205. 




INDEX. 


267 


Production. 199-200. 

Underground development, 200. 
Morton mine, 197-198. 

Geology, 197-198. 

History, 197. 

Location, 197. 

Seay mine, 205. 

Williams mine, 191-192. 

Description, 191-192. 

Location, 191. 

Mines in Goochland and Fluvanna 
counties, 118-183. 

Atmore, Kent, and other properties, 
142. 

Belzoro mine, 139-141. 

Descriptive geology, 140-141. 
History, 139-140. 

Location, 139. 

Production, 141. 

Benton mine, 152. 

Description. 152. 

Location, 152. 

Bertha and Edith mine, 142-144. 
Description of veins and country 
rock, 143-144. 

History, 142-143. 

Location, 142. 

Bowles mine, 175. 

History and general description, 
172 173. 

Location, 175. 

Busby mine, 146-147. 

Collins mine, 141. 

Fleming mine, 151. 

History and description, 151. 
Location, 151. 

Gold Hill vein system, 176-179. 
Bowles mine, 178-179. 

Country rock, 176-177. 
Introduction, 176. 

MeGloam mine, 177-178. 

Shaw mine, 178. 

Gold prospects southwest of the 
Scotia mine, 173-175. 

Grannison mine, 142. 

Hughes mine, 181-183. 

Equipment, 181-182. 

Geology of veins and country 
rock, 182-183. 

History, 181. 

Location, 181. 

Underground development and de¬ 
scription of veins, 182. 

Morgan mine, 141-142. 

Moss mine, 144-146. 

Descriptive geology, 145. 

History, 144-145. 

Location, 144. 

Page mine, 179-180. 


Payne tract, 147. 

Pryor tract, 144. 

Scotia mine, 172-173. 

History and description, 172-173. 
Location, 172. 

Shannon Hill, 151-152. 

Snead mine, 180-181. 

Geology, 180-181. 

History, 180. 

Location, ISO. 

Tellurium mine, 152-155. 

History and description, 153-155. 
Location, 152. 

Present underground develop¬ 
ment, 155. 

Tellurium vein system, 155-172. 
Detailed descriptions of veins and 
wall rock, 157-172. 

General description of veins and 
country rock, 155-157. 

Waller mine, 148-151. 

Descriptive geology, 148-151. 
History, 148. 

Location, 148. 

Young American mine, 118-139. 
Detailed descriptions of the veins 
and wall rock, 122-139. 

General description of the geolo¬ 
gy, 120-122. 

History, 118-119. 

Location, 118. 

Present equipment, 119. 
Underground development, 119- 
120. 

Gold prospects southwest of the Scotia 
mine, 173-175. 

Gold veins. Lightfoot mine, 207. 
Goochland and Fluvanna counties, mines 
in, (See Mines in Goochland 
and Fluvanna counties). 
Gneisses, 36-39. 

Details of occurrences, 38-39. 

General character and distribution, 
36-37. 

Genesis, 37. 

Granite at Greelev mine, 82. 

Grannison mine, 86, 142. 

Greeley mine, 205-207. 

History, 205-206. 

Location, 205. 

Veins and country rock, 206-207. 
Greenstone schists, 47-51. 

Age, 49. 

Details of occurrences, 49-51. 
Anaconda mine, 50-51. 

-Hughes mine, 51. 

Lightfoot farm, 50. 

Palmyra, 51. 

Shores, 51. 



268 


INDEX. 


Slate River, 49-50. 

History, 5-9. 

Anaconda mine, 243-244. 
Belzoro mine, 139-140. 

Bertha and Edith mine, 142- 
143. 

Bondurant mine, 192-193. 
Buckingham mine, 190-191. 
Burnett mine, 196. 

Greeley mine, 205-206. 

Hughes mine, 181. 

Lightfoot mine, 207, 241. 
London and Virginia mine, 183- 
184. 

Morrow mine, 198-199. 

Morton mine, 197. 

Moss mine, 144-145. 

New Canton mines, 246-247. 
Snead mine, 180. 

Waller mine, 148. 

Young American mine, 118-119. 
History and description, Bowles mine, 

172-173. 

Fleming mine, 
151. 

Scotia mine. 
172-173. 

Tellurium mine, 
153-155. 

Hobson tract, 197. 

Hornblende-bearing quartzites, 23. 
Hornblende schists, 34-36. 

Details of occurrences, 35-36. 

General character and distribution, 
34-35. 

Hudgins mine, 248, 256-257. 

Hughes farm, 80. 

Hughes mine, 51, 181-183. 

Equipment, 181-182. 

Geology of veins and country rock, 
182-183. 

History, 181. 

Location, 181. 

Underground development and de¬ 
scription of veins, 182. 
Introduction, 1. 

acknowledgments, 1. 
contact metamorphism, 106. 
descriptive geologv and petrography, 
13. 

genetic relations of the gold deposits, 
208-209. 

Gold Hill vein system, 176. 
gold mines of the district, 118. 
physiography, 88. 
structure and metamorphism, 98. 
tellurium vein system, 155. 
Introductory' statement, granites, etc., 
53-54. 


James River section, 59-60. 

James River section across granite con¬ 
tact, 107-112. 

Johnson mine, 247, 254-256. 

Jointing, i00. 

Knotted schists, 29-34. 

Details of occurrences, 30-34. 

General character and distribution, 
29-30. 

Lantana, 24-25, 36, 61, 69. 

Lightfoot farm, 50. 

Lightfoot mine, copper. 241-243. 

Country rock, 241-242. 

History, 241. 

Location, 241. 

Ore-denosit, 242-243. 

Lightfoot mine, gold, 207. 

Gold veins, 207. 

History, 207. 

Location, 207. 

List of minerals in the gold veins of the 
James River basin area, 211- 
212. 

Little Byrd Creek. 60-61. 

Location, Anaconda mine, 243. 

Anderson mine, 195. 

Belzoro mine, 152. 

Benton mine, 152. 

Bertha and Edith mine, 142. 
Bondurant mine, 192. 

Bowles mine, 175. 

Buckingham mine, 190. 
Burnett mine, 196. 

Fleming mine, 151. 

Flood mine, 195. 

Greeley mine, 205. 

Hughes mine, 181. 

James River basin gold belt, 
2-3. 

Lightfoot mine, 207, 241. 
London and Virginia mine, 
183. 

Morrow mine, 198. 

Morton mine, 197. 

Moss mine, 144. 

Scotia mine, 172. 

Snead mine, 180-181. 

Tellurium mine, 152. 

Waller mine, 148. 

Williams mine, 191. 

Young American mine, 118. 
London and Virginia mine, 19, 25-26, 
183-190. 

Description of vein, 187-190. 
Descriptive geology, 184-187. 

History, 183-184. 

Location, 183. 

Long Island Creek, 42, 85. 

McGloam mine, 78-79, 177-178. 



INDEX. 


269 


McKenna mine, 247, 253-254. 

Margaret mine, 248. 

Metamorphic features. 105-114. 

Contact metamorphism, 106. 

Regional metamorphism, 105-106. 
Mineral composition of the veins, 209- 
216. 

Description of the gangue minerals, 
213-214. 

Description of the ore minerals, 213- 
214. 

List of minerals in the gold veins of 
the James River basin, 211- 
212 . 

81111111131 - 7 , 215-216. 

Mines in Buckingham County, 183-207. 
Anderson mine, 195. 

Bondurant mine, 192-195. 

Buckingham mine, 190-191. 

Burnett mine, 196. 

Flood mine, 195. 

Gilliam mine, 195. 

Greeley mine, 205-207. 

Hobson tract, 197. 

Lightfoot mine, 207. 

London and Virginia mine, 183-190. 
Morrow mine, 198-205. 

Morton mine, 197-198. 

Seay mine, 205. 

Williams mine, 191-192. 

Mines in Goochland and Fluvanna coun¬ 
ties. 118-183. 

Atmore, Kent, and other properties, 
142. 

Belzoro mine, 139-141. 

Benton mine, 152. 

Bertha and Edith mine, 142-144. 
Bowles mine, 175. 

Busby mine, 146-147. 

Collins mine, 141. 

Fleming mine, 151. 

Gold Hill vein system, 176-179. 

Gold prospects southwest of the Scotia 
mine, 173-175. 

Grannison mine, 142. 

Hughes mine, 181-183. 

Morgan mine, 141-142. 

Moss mine, 144-146. 

Page mine, 179-180. 

Payne tract, 147. 

Pryor tract, 144. 

Scotia mine, 172-173. 

Shannon Hill, 151-152. 

Snead mine, 180-181. 

Tellurium mine, 152-155. 

Tellurium vein system, 155-172. 

Waller mine, 148-151. 

Young American mine, 118-139. 
Morgan mine, 141-142. 


Morrow mine, 198-205. 

Description of ores, 204-205. 
Descriptive geology, 200-204. 

Histopq 198-199. 

Location, 198. 

Placers, 205. 

Production, 199-200. 

Underground development, 200 . 
Morton mine, 197-198. 

Geology, 197-198. 

Historv, 197. ' 

Location, 197. 

Moss mine, 144-146. 

Descriptive geology 145 , 

History, 144-145. 

Location, 144. 

Nature of the solutions, 217-219. 

New Canton, 30-34, 35, 71-72. 

New Canton-Dillwyn road, 25. 

New Canton mines, 246-259. 

Comparison with other ores of the dis¬ 
trict, 259. 

Detailed description of the ore and in¬ 
closing rock, 250-257. 

General description of the geology, 
248-250. 

Genesis of the New Canton ore depos¬ 
its, 257-259. 

History, 246-247. 

Ordovician, 39-46, 116. 

Conglomerate, 40-42. 

General statement, 39-40. 

Quartzite, 42. 

Schist, 42-43. 

Slate, 43-46. 

Tuff, 43. 

Ore deposit, Lightfoot mine, 241. 

Origin of the spaces occupied by the 
veins, 222-231. 

Other localities, 62, 87. 
quartz-sericite schists, 26. 
ferruginous quartzites, 21 - 22 . 

Outline of geological history, 114-117. 
Cambrian, 115-116. 

Ordovician, 116. 

Pre-Cambrian, 115. 

Triassic, 116-117. 

Page mine, 179-180. 

Palmyra, 51, 53, 84-85. 

Payne farm, 70-71. 

Payne tract, 147. 

Pegmatite belt, 59-62. 

Detailed descriptions, 59-62. 

General description, 59. 

Pemberton, 55-56, 87. 

Penlan, 41. 

Physiographic history, 93-97. 
Physiography, 88-97. 

Drainage, 91-93. 




INDEX. 


270 


Introduction, 88. 

Physiographic history, 03-97. 

Relief, 88-91. 

Placers, 235-240. 

Porphyries, 82-84. 

Details of occurrences, 82-84. 
Distribution and general description, 
S2. 

Pre-Cambrian, 14-39, 47-53, 115. 

Cyanite schists, 26-29. 

Ferruginous quartzite, 19-22. 
Garnetiferous quartzites, 22-23. 
General statement, 14-15. 

Gneisses, 36-39. 

Greenstone schists, 47-51. 
Horneblende-bearing quartzites, 23. 
Hornblende schists, 34-36. 

Knotted schists, 29-34. 

Quartz-feldspar porphyries, 51-52. 
Quartzite, 15-19. 

Quartz-sericite schist, 23-26. 

Rhyolites, 52-53. 

Pre-Cambrian and Cambrian, 53-84. 
Granites, their associated pegmatites 
and hornblende schists, 53-82. 
Porphyries, 82-84. 

Present equipment, Young American 
mine, 119. 

Present underground development, 155. 
Previous geologic work, 9-12. 

Previous theories, 208-209. 

Production, 9. 

Belzoro mine, 141. 

Morrow mine, 199-200. 

Pryor tract, 144. 

Quartz-feldspar porphyries, 51-52. 
Quartzite, 15-19, 42. 

Details of occurrences, 16-19. 

General character and distribution, 
15-16. 

Quartz-sericite schists, 23-26. 

Details of occurrences, 24-26. 

General character and distribution, 
23-24. 

Genesis, 24. 

Regional metamorphism, 105-106. 
Relations of the hornblende schists to 
the granites, 103-105. 

Relief, 88-91. 

Rhyolites, 52-53. 

Details of occurrences, 52-53. 

General description and age relations, 
52. 

Rivanna Mills, 73-75. 

Rivanna River section across granite 
contact, 112-113. 

Rocks igneous in origin, 47-87. 

Cambrian or post-Cambrian, 84-85. 
General classification, 47. 


Pre-Cambrian, 47-53. 

Pre-Cambrian and Cambrian, 53-84. 
Triassic, 85-87. 

Rocks sedimentary in origin, 14-47. 
General classification, 14. 

Ordovician. 39-46. 

Pre-Cambrian. 14-39. 

Triassic, 46-47. 

Rosney granite area, 80-82. 

Schist, 42-43. 

Schistosity, 101-102. 

Scotia mine, 21, 172-173. 

History and description, 172-173. 
Location, 172. 

Seay mine, 205. 

Secondary enrichment, 232-233. 

Shannon Hill, 61, 151-152. 

Shaw mine, 178. 

Shores, 51. 

Slate, 43-46. 

Details of occurrences, 44-46. 

General character and distribution, 
43-44. 

Slate River, 49-50, 52. 

Snead mine, 180-181. 

Geology, 180-181. 

History, 180. 

Location, 180. 

Soil, 4. 

Source of the material, 219-221. 

Stage Junction, 34. 

Stearnes, 72-73. 

Stokes, 56. 

Strathmore, 34. 

Structure and metamorphism, 98-117. 

' Introduction, 98. 

Outline of geological history, 114-117. 
Cambrian, 115-116. 

Ordovician, 116. 

Pre-Cambrian, 115. 

Triassic, 116-117. 

Metamorphic features, 105-114. 
Contact metamorphism, 106. 

Detailed descriptions of contact 
phenomena, 107-114. 

Jaraes River section across 
granite contact, 107-112. 
Rivanna River section across 
granite contact, 112-113. 
Veins, 113. 

Willis Mountain, 113-114. 
Regional metamorphism, 105-106. 
Structural features, 98-105. 

Faulting, 100. 

Folding, 98-99. 

Jointing, 100. 

Relations of the hornblende schists 
to the granites, 103-105. 
Schistosity, 101-102. 



INDEX. 


271 


Structural relations of the granite, 
102-103. 

Structural features, 98-105. 

Faulting. 100. 

Folding, 98-99. 

Jointing, 100. 

Relations of the hornblende schists to 
the granites, 103-105. 

Schistosity, 101-102. 

Structural relations of the granite. 
102-103. 

Structural relations of the granite, 102- 
103. 

Summary, 215-210. 

Tabscott, 70. 

Tellurium mine, 18-19, 152-155. 

History and description, 153-155. 

Location, 152. 

Present underground development, 
155. 

Tellurium schists, 34. 

Tellurium vein system, 155-172. 

Detailed descriptions of veins and wall 
rock, 157-172. 

General description of wins and coun¬ 
try rock, 155-157. 

Topography, 3. 

Trent farm. 28-29. 71. 

Trenton Mills, 71. 

Triassic, 48-47, 85-87, 116-117. 


Tuff, 43. 

Types of copper deposits, 209, 241. 
Underground development, Morrow mine, 

200 . 

Young Amer¬ 
ican mine, 
119-120. 

Underground development and descrip¬ 
tion of veins, Hughes mine, 182. 
Veins, 113. 

Veins and country rock, Greeley mine, 
205-207. 

Waller mine, 148-151. 

Descriptive geology, 148-151. 

History, 148. 

Location, 148. 

Webb tract, 19-20. 

Williams mine, 191-192. 

Description, 191-192. 

Location, 191. 

Willis Mountain, 27-28, 113-114. 

Young American mine, 38, 118-139. 
Detailed descriptions of the veins and 
wall rock, 122-139. 

General description of the geolosy. 
120 - 122 . 

History, 118-119. 

Location, 118. 

Present equipment, 119. 

Underground development, 119-120. 































































